In 2009, Randy Wells was a surprisingly effective cog in the Chicago Cubs’ rotation. The converted catcher and returned 2007 Rule V pick of the Blue Jays posted a 3.05 ERA in 165.1 innings pitched, placing 10th among qualified National League starters. This season, however, Wells has fallen to a 4.92 ERA in 78.2 frames. Has the 27-year-old righty regressed significantly, or are better days ahead?

While Wells’ ’09 performance was sturdy, it is important to note that his gaudy ERA overstated the extent of his dominance. With 5.66 K/9 and 2.5 BB/9, Wells had a more modest 4.24 xFIP. The ERA/xFIP dichotomy was the result of a fairly high 76% rate of stranding base runners (the MLB average is usually around 70-72%, though pitcher skill does play some role) and a home run/fly ball rate of eight percent (11% MLB average).

Extreme strand and HR/FB rates have a way of returning toward those big league averages, and we’ve seen that from Wells in 2010 — he’s leaving 67.8% of runners on base, and 9.2% of his fly balls are reaching the bleachers. While a reversal of fortune on those fronts should have been expected, Wells has seemingly gone to the other end of the luck spectrum this season. He’s got a .355 batting average on balls in play, compared to .294 in 2009. Among qualified starting pitchers, only Pittsburgh’s Zach Duke has a higher BABIP.

The first thing that sticks out regarding Wells’ performance on balls put in play is his line drive rate. It’s 25.1% this year, highest among starters and leaps and bounds above his 18.8% mark from last season. Line drives aren’t the most stable metric from season to season, but we know that bad things happen on batted balls classified as liners — line drives in the NL this season have a .975 slugging percentage and a .715 BABIP. Wells’ liners have a .965 SLG% and a .754 BABIP. That’s certainly a contributing factor to his inflated BABIP. But what makes this finding confusing is that just about every other performance measure suggests that Wells isn’t getting hit hard at all.

So far, he has 7.09 K/9. He’s whiffing 18 percent of batters faced this year, up from 15 percent in 2009. Wells’ swinging strike rate, 8.1% last season, has climbed to 10.9% (8-9% MLB average). His overall contact rate is 77.1% in 2010, compared to 81.8% last year (80-81% MLB average). Relative to the big league average, Randy’s outside swing percentage is up — he’s outpacing the MLB norm by 17 percent this year (33.1 O-Swing, 28.2 MLB average) after surpassing it by 11 percent last year (27.8 O-Swing, 25.1 MLB average).

Wells is getting swinging strikes when throwing a fastball 6.8 percent in 2010, compared to 4.3% last season (the MLB average is around six. His slider is getting slightly more whiffs (13.3% in ’10 to 12.8% in ’09, 13.6% MLB average) and his changeup has a 19.4% whiff rate, up considerably from last year’s 13.1% clip (12.6% MLB average). None of these numbers suggest he has gotten easier to hit.

In addition to getting more whiffs, Wells has actually lowered his walk rate slightly to 2.29 BB/9. He continues to get ahead in the count often, with a 61.6 first pitch strike percentage (61.4% last year, 58% MLB average).

Overall, Wells’ xFIP is a tidy 3.68 — over a half-run lower than his 2009 figure. That line drive rate bears watching, but there are many positives to be found in Wells’ “disappointing” follow-up to his celebrated rookie campaign. If he’s available in your league (and with a 51% Yahoo ownership rate, there’s a decent chance that he is), do your team a favor and scoop up a quality starter on the cheap.

J.D. Martin, Nationals (Owned in one percent of Yahoo Leagues)

While Washington’s non-Strasburg starters have been lackluster this season, with a collective 4.68 xFIP that ranks 15th in the NL, Martin’s solid performance so far might not buy him much job security. Scott Olsen (shoulder inflammation) could be back next month, as could Chien-Ming Wang (shoulder). Jordan Zimmermann (Tommy John surgery) is another possibility to pitch in August or September. Returns for Jason Marquis (elbow) and Ross Detwiler (hip) are less certain.

In the meantime, however, NL-only players could do worse. Martin, 27, was a supplemental first-round pick of the Cleveland Indians in the 2001 draft. The 6-4, 200 pound righty once rated prominently on prospect lists, cracking Baseball America’s top 100 prior to 2002. Sadly, injury derailed his ascent to the majors — Martin underwent Tommy John surgery in 2005. His standing in Cleveland’s system slipped, as he was shifted mostly to relief work in 2008, and he then signed as a minor league free agent with the Nationals prior to 2009.

Martin’s a soft-tosser — he features an 87-88 MPH fastball, a mid-80’s cutter, a low-70’s curve and a low-80’s changeup — but he has a quality minor league track record and exceptional control. Last season at Triple-A Syracuse, Martin had 6.44 K/9, 1.02 BB/9, 0.41 HR/9 and a 2.77 FIP in 88 innings pitched. Prior to his late-May call-up in 2010, he whiffed 5.5 per nine, walked 1.8 per nine, surrendered 0.7 HR/9 and held a 3.75 FIP in 41 IP.

Logging 102.1 big league frames over the past two years, Martin has 4.84 K/9, 2.2 BB/9 and a 5.09 xFIP. There’s no guarantee that he’ll succeed — Martin won’t miss many bats, and he’s a fly ball pitcher (37.4 GB%) who has experienced problems with the long ball (1.67 HR/9) — but he could be a decent mid-to-back-end starter. ZiPS projects 5.63 K/9, 2.09 BB/9, 1.29 HR/9 and a 4.44 FIP for the rest of 2010.

Ike Davis, Mets (16%)

The 18th overall pick in the 2008 draft experienced a famous power outage after signing (.256/.326/.326, 0 HR in 239 New York-Penn League PA), causing some Mets fans to rashly wonder if the team made a mistake. Since then, Davis has raked. He batted a combined .298/.381/.524 in 488 PA between the High-A Florida State League and the Double-A Eastern League last season, walking 11.7 percent of the time, punching out 26.1 percent and posting a .226 ISO while going yard 20 times.

After a productive Arizona Fall League stint and a week-plus at the Triple-A level, Davis was bumped up to the majors early in 2010. Davis, 23, has made a seamless transition. The 6-5 lefty hitter has a .261/.345/.447 triple-slash in 226 PA, with a .346 wOBA. He’s showing decent pop, with a .186 ISO, and he’s walking in 11.1 percent of his trips to the plate. Plus, those dugout flips are so freakin’ cool.

Davis has been a fairly aggressive batter, swinging at 29.4% of pitches thrown outside of the strike zone (28.2% MLB average this season), but he holds that double-digit walk rate as a result of seeing very few offerings over the plate. Pitchers are giving Isaac Benjamin an in-zone pitch just 38.3 percent of the time, the lowest rate among qualified MLB hitters (47.3% MLB average). On a related note, opponents are reluctant to give him fastballs — Davis is getting a fastball under 50% of the time, eighth-lowest among big league batsmen. So far, the opposition’s strategy against Ike seems to be, “feed him off-speed stuff off the plate and hope for a chase.” It’ll be interesting to see if that approach shifts in the months to come.

Philadelphia Phillies placed LHP Antonio Bastardo (elbow) on the DL; recalled RHP Scott Mathieson from Triple-A Lehigh Valley.

A 17th-round pick in the 2002 draft, Mathieson boasts low-to-mid-90’s gas, a sharp slider and a workable changeup. So why is the 26-year-old righty making his first big league appearance since September of 2006? Since Mathieson reached the majors in the summer of ’06, his career aspirations have been assailed by one injury after another.

The 6-3, 190 pound Canadian emerged as a quality starting pitching prospect in the Phillies’ system. Back in 2004, Baseball America noted that Mathieson had filled out his frame since signing and gained considerable velocity on a fastball that rarely left the mid-80’s in high school. Apparently dubbed “The Goose,” Mathieson ascended Philly’s list of farm talents — number 14 prior to 2005, sixth before the 2005 campaign and fifth leading up to 2006.

His performance improved with each promotion. As a 20-year-old in the Low-A South Atlantic League in ’04, Mathieson had 7.7 K/9, 3.4 BB/9 and a 4.32 ERA. In ’05, he whiffed 8.6, walked 2.5 and had a 4.22 FIP in the High-A Florida State League. Mathieson posted a combined 3.20 FIP, 9.5 K/9 and 2.7 B/9 the following season while splitting the year between the Double-A Eastern League and the Triple-A International League. He was a fly ball pitcher, with GB rates under forty percent all along the way, but Mathieson’s velocity, K rates and improved breaking ball (he switched from a curve to a slider) earned him MLB innings in ’06.

That first foray in the majors was disastrous. Sure, the results (37.1 IP, 6.75 K/9, 3.86 BB/9, 7.47 ERA, 4.91 xFIP) weren’t great. But it’s what happened on September 2nd — he felt a “shooting pain” in his elbow — that made it a nightmare. Mathieson was shut down and underwent Tommy John surgery in late September.

While the then-23-year-old began a rehab assignment toward the end of the 2007 season, it was transient. Mathieson had to come out of a late-August game at Double-A Reading and had ulnar nerve transposition surgery that September. He didn’t throw a pitch in 2008, as he became twice Tommy John‘d that May.

In June of 2009, Mathieson returned to the bump as a reliever. Pitching mostly at Reading while also getting some work in rookie ball and at High-A Clearwater, he had 8.5 K/9, 3.3 BB/9 and a 3.08 FIP in 32.1 innings. BA ranked Mathieson 15th in Philly’s system heading into 2010, saying that he could “be an asset as a set-up man if he can stay healthy.” Our own Marc Hulet noted Mathieson’s high-octane performance in the Arizona Fall League and ranked him at the tenth best talent in the Phillies’ organization.

Prior to getting the call, Mathieson was pitching well with the Iron Pigs — 29.2 IP, 10.3 K/9, 3.6 BB/9 and a mid-three’s FIP. Per Minor League Splits, his park-and-luck-adjusted major league equivalent line is 8.3 K/9, 4.75 BB/9 and a 4.90 FIP. Mathieson’s GB% remains under 40 as a reliever, a trait that could cause some headaches at Citizens Bank Park (three-year HR park factor of 114, according to the Bill James Handbook).

Mathieson likely won’t challenge Brad Lidge or an impressive Jose Contreras for late inning opportunities at this point, but he’s worth watching. If this persevering flame-thrower can stay healthy and limit the long ball damage, he could be a nice addition to a Phillies ‘pen that ranks a middling ninth in the NL in xFIP.

Toronto Blue Jays 2B Aaron Hill entered 2010 flying high. After all, Hill hammered pitchers for a .286/.330/.499 line last season, with 36 home runs and a .357 wOBA that placed behind just Ben Zobrist, Chase Utley, Robinson Cano, Dustin Pedroia and Ian Kinsler among keystone players. The LSU product’s unprecedented power surge (.213 Isolated Power) wasn’t expected to be repeated this year, but ZiPS and CHONE figured he’d be an asset at the plate again:

ZiPS: .275/.323/.447, .172 ISO, .337 wOBA
CHONE: .282/.332/.453, .171 ISO, .342 wOBA

Fantasy players bought the breakout performance big-time — according to KFFL, Hill’s ADP for 2010 was 49th overall. But, instead of providing a potent bat at an up-the-middle position, Hill has a .197/.289/.370 triple-slash and a putrid .296 wOBA. Despite the hefty investment, some owners are cutting ties altogether. Hill is on the waiver wire in nine percent of ESPN leagues, and 17 percent of Yahoo leagues. What’s going on here?

Two numbers jump off Hill’s stat sheet — his .192 batting average on balls in play and his 9.7% line drive rate, both lowest among qualified major league hitters. During his big league career, Hill has a .298 BABIP and he has hit line drives at a 19.3 percent clip.

Those missing line drives have been classified as fly balls, as Hill’s 48.9 FB% is well north of his 39.5 percent rate. And more of those flies are of the weak variety — his infield/fly ball rate is 14 percent. That’s nearly double the MLB average and above his career 10.1 IF/FB%. Infield flies are the closest thing to an automatic out on a ball put in play, so they’re BABIP killers.

Another potential cause of Hill’s poor hitting is his expanded strike zone. His outside swing percentage was below the MLB average each season from 2005-2008, and it was about six percent above the big league average last season. In 2010, he’s hacking at 33.3 percent of off-the-plate pitches, compared to the 28.1% MLB average. As a proportion of the big league average, that’s +19 percent (33.3 divided by 28.1). Also, he’s making more (likely weak) contact with those pitches thrown out of the zone — his O-Contact% was below the major league average the previous three seasons, but he has put the bat on the ball 71.9% of the time on outside pitches this year. The MLB average in 2010 is 66.4%, so Hill’s O-Contact is plus-eight percent.

Hill’s plate discipline this season has been less-than-stellar. But even so, there are reasons to expect a rebound to league-average hitting. His BABIP on grounders this year (.153) is 90 points lower than his career average (.243). His BABIP on fly balls (.081) is 34 points lower than his career mark (.115). Hill’s still hitting for power (.173 ISO), and his walk rate is in the double-digits (10.6 BB%) despite his chasing more pitches than usual, the result of opponents throwing him fewer pitches in the zone (46.2%, compared to the 47.3% MLB average).

The 28-year-old second baseman has a .258/.314/.431 rest-of-season ZiPS, with a .329 wOBA. CHONE projects a .268/.328/.451 line, which is roughly a .335 wOBA. His career triple-slash? .278/.333/.429, and his wOBA is .332.

Hill’s not the new Jeff Kent He has fallen into some bad habits, which have contributed to his struggles. However, he’s not a lost cause, either. Hill retains a good deal of pop, and he should resume being a solid, if unspectacular fantasy option with some better bounces and a plate approach reboot.

Anibal Sanchez has endured a star-crossed career. The former Red Sox farmhand, picked up by the Marlins as part of the Josh Beckett/Mike Lowell/Hanley Ramirez mega-deal in November of 2005, punched out over ten batters per nine innings in the minors. In its 2006 Prospect Handbook, Baseball America remarked that while Florida desired Jon Lester in the Beckett deal, Sanchez was “a premium prospect in his own right.” And on September 6, 2006, Sanchez sat on top of the baseball world, no-hitting the Arizona Diamondbacks in the thirteenth start of his rookie season.

Over the next three years, however, Sanchez would spend more time rehabbing than trying to retire big league batters. While a Sox prospect, he overcame 2003 surgery to transpose a nerve in his right elbow. But injuries again crept into the picture — Sanchez underwent labrum surgery in May of 2007. After a near-15 month absence from a major league mound, he returned on trade deadline day of 2008. Unfortunately, shoulder woes derailed his 2009 season as well — he spent nearly four months on the DL. Over the 2007-2009 period, Sanchez logged just 167.2 MLB innings.

So far this season, it appears as though Sanchez is finally making good on those predictions of acedom. In 81 frames, the 26-year-old right-hander has a 3.22 ERA. That puts him in the same company as studs like Mat Latos and Tommy Hanson. Fantasy owners have been slow to get on board, though, as Sanchez is owned in just 38 percent of Yahoo leagues. Should more players be scrambling to the waiver wire to snag Anibal, or is that reticence well-justified?

During his first 13 starts of the season, Sanchez has 6.78 K/9, 3.44 BB/9 and a 44.3 percent groundball rate. If those numbers sound rather run-of-the-mill, that’s because they are — in 2010, the average MLB hurler has whiffed 7.02 batters per nine innings, with 3.45 BB/9 and a groundball rate around 44 percent. During his big league career, Sanchez has 6.64 K/9, 4.19 BB/9 and a 43.4 GB%. He’s issuing fewer walks than in years past, which is certainly a positive. But there’s nothing here that portends to a great leap forward.

Similarly, his plate discipline stats show some, though not a ton, of improvement. Sanchez’s rate of first pitch strikes is up, sitting at 59.4 percent (55.6% career average, 58% MLB average). Also, he’s getting swings on pitches out of the zone 29.6% (28.1% MLB average), the first time his O-Swing has surpassed the big league average. But his 8.9 percent swinging strike rate is right in line with his 8.7% career mark (8-9% MLB average), as is his 80.8% contact rate (80.2% career average, 80-81% MLB average).

So how is Sanchez’s ERA in the low three’s? Homers. Or rather, a lack thereof. When opponents loft a fly ball against Sanchez, it’s leaving the yard just 3.4 percent of the time. That’s the fifth-lowest rate among qualified big league starters. For comparison, the major league average is about 11 percent, and Sanchez’s career rate entering 2010 was 8.7 percent. Dolphin…er, Sun Life Stadium had a neutral HR/FB park factor over the past few years. There’s very little chance that Sanchez continues to see so many balls die at the warning track.

His xFIP, based on strikeouts, walks and a normalized HR/FB rate, is 4.34. That’s better than his recent work — 4.43 in 2008 and 4.64 last season — but not greatly so. Sanchez has essentially been a slightly above-average starter who has gotten some big breaks in the dinger department. I think Sanchez is certainly worth a roster spot in NL-only leagues, and he could be an option in deeper mixed formats. But keep in mind that, between his voluminous injury history and ERA drop based on a factor largely out of the pitcher’s control, Sanchez is far from a sure thing.

Oakland Athletics acquired OF/1B Conor Jackson from the Arizona Diamondbacks for RHP Sam Demel.

Jackson, 28, is under team control through the 2011 season. The 2003 first-round pick out of Cal established himself as a fairly patient hitter with mid range pop over the 2006-2008 seasons, hitting a combined .292/.371/.450 with a .361 wOBA. Adjusting for park and league factors, Jackson’s lumber was 14 percent better than average (114 wRC+). That’s not overwhelming for a guy who mainly manned first base, but Jackson controlled the zone (10.1 BB%, 12.8 K%), showed adequate power (.158 ISO) and improved his fantasy appeal by qualifying in the outfield during the ’08 season.

The past two years haven’t been nearly as kind. Jackson battled Valley Fever in 2009, limiting him to just 110 PA. He batted .182/.264/.253, with a .251 wOBA. Slowed by a right hamstring injury that required a DL stint in April, Jackson’s got a .298 wOBA and a .238/.326/.331 triple-slash in 172 PA this season. His ISO, .071 in 2009, hasn’t cracked triple-digits in 2010 either (.093).

In Oakland, Jackson figures to take over most of the playing time in left field. He’s worth a flyer in AL-only formats, but it’s hard to know how he’ll hit in the green and gold, given the uncertainty regarding his health. If Jackson is moving past the illness that sapped his strength, he could return to the .350-.360 wOBA range. Given that he has rated as about average in an outfield corner to this point, that would make Jackson a decent starting option for the A’s.

Mixed-leaguers probably want a player with higher upside and greater certainty, though. It’s also worth noting that Jackson will be moving from Chase Field, which (per the Bill James Handbook) increased run-scoring 15 percent and homers seven percent compared to a neutral park over the 2007-2009 seasons, to the Coliseum, which depressed runs nine percent and dingers 10 percent over the same time frame. That won’t help his chances of regaining fantasy relevance.

With Jackson no longer in the desert, Gerardo Parra will presumably get the majority of PT in left for the Diamondbacks. The 23-year-old lefty batter, rated as the 88th-best prospect in the game by Baseball America prior to 2009, has a .281/.319/.400 major league line in 609 PA over the past two seasons. The Venezuelan native has a .309 wOBA and a 82 wRC+, as he has rarely walked (5.4 BB%) or laced the ball into the gaps (.119 ISO).

Swinging early and often getting behind in the count (career 64.4 first pitch strike percentage, compared to the 58% MLB average), Parra has hit grounders at a 53.5% clip. He’s a good defender in an outfielder corner, but his offensive ceiling is subject to debate –Parra’s not uber-projectable at 5-11 and 195 pounds, and he didn’t display much thump in the minors (career .126 ISO). He was generally young for the levels at which he played, but Baseball America capped his home run power at the low-to-mid-teens, remarking that “if he has to move to an outfield corner he starts to look like a tweener.”

Demel, meanwhile, is expected to join a wretched D-Backs pen that ranks dead last in xFIP (5.16) and Win Probability Added (-6.88). A third-round pick in the 2007 draft out of TCU, Demel has missed lots of lumber as a pro (10 K/9) but has usually struggled to locate (4.5 BB/9). While the righty didn’t crack BA’s list of top 30 A’s prospects heading into 2010, Demel has added a cut fastball to his low-90’s fastball, changeup and erratic slider. In 28.2 IP with Triple-A Sacramento, the 24-year-old had 8.8 K/9, 2.8 BB/9 and a characteristically strong ground ball rate (49.4%; his overall GB% in the minors is 54.5). Demel’s worth monitoring, particularly if Arizona shops Chad Qualls to a team that focuses more on his very good track record and 3.56 xFIP this season instead of his bloated ERA.

Stephen Strasburg, Nationals

Yeah, I know — kinda obvious. But Strasburg’s first two big league starts are well worth discussing. The hoopla surrounding the San Diego State Aztec reached mythical proportions typically reserved for the likes of Big Foot, Chupacabra and Loch Ness, but Strasburg has been highly impressive.

The 21-year-old righty ripped apart minor league batters before getting the call — in 55.1 IP between Double-A Harrisburg and Triple-A Syracuse, he had 10.6 K/9, 2.1 BB/9 and a FIP slightly above two. When opponents weren’t whiffing, they were hitting weak grounders (Strasburg’s GB% was 64.9). While his second MLB start against Cleveland proved that he is, in fact a sentient being capable of error, Strasburg has a 22/5 K/BB ratio in 12.1 frames so far.

He’s sitting 98 with the four-seamer, 96 with the two-seamer and also features a low-80’s curve with two-plane break and a 90-91 MPH change that drops seven inches more than his four-seamer (4-4.5 inch big league average). His swinging strike rate is 15.3. There’s not much else to say, other than Strasburg really is worthy of the attention that he receives.

Colby Rasmus, Cardinals

Rasmus, 23, has followed up a quality rookie season with a great leap forward at the plate. In 219 PA, he’s hitting .293/.399/.582, with a .414 wOBA that ranks in the top 10 among MLB hitters. Clearly, Rasmus won’t keep up this pace. He’s benefitting from some fortunate bounces, with a .375 BABIP that’s well ahead of his .319 expected BABIP. But even so, he’s working the count and crushing the ball.

Swinging at 23.3 percent of pitches out of the zone (28.1% MLB average), Rasmus is drawing ball four in 14.6% of his PA. His Isolated Power, .156 last season, is .288 in 2010. All of that taking and raking has come with more swings and misses (33.2 K%, compared to 20% in ’09), but it’s a trade well worth making. Rasmus likely won’t keep hitting homers nearly 21 percent of the time that he lofts a fly ball into the air — ZiPS projects a .266/.342/.447 line for the rest of 2010, and CHONE a .259/.339/.442 triple-slash. I’d take the over on those forecasts, however.

Brandon Morrow, Blue Jays

Definitively a starter with Toronto after years of role-related drama in Seattle, Morrow has been considerably better than his ERA (5.14) implies. He’s got 10.29 K/9, 4.89 BB/9 and a 3.99 xFIP in 70 innings pitched. Morrow still struggles to find the strike zone at times — his first pitch strike percentage is 53.8 (58.3% MLB average) — but he’s missing lumber at an elite rate.

With an 11 percent swinging strike rate, Morrow ranks in the top 10 among qualified starters (the MLB average is 8.2%). His contact rate of 74.4% is well above the 81.1% big league average and places behind just Clayton Kershaw, Tim Lincecum and teammate Ricky Romero. The whiff rates on Morrow’s 94 MPH four-seam fastball and upper-80’s slider are stratospheric — 10.6% for the four-seamer (6% MLB average) and 26.7% for the slider (13.6% MLB average). This guy’s probably still available on the waiver wire, too, as Morrow’s owned in just 15% of Yahoo leagues.

Rick Porcello, Tigers

Porcello’s 21, and his career could take any number of paths over the coming years. But he hasn’t made progress during his sophomore season. The New Jersey prep product is punching out fewer batters this year than in 2009 (4.02 K/9, compared to 4.69 K/9), with a few more walks (2.91 BB/9, 2.74 BB/9 in ’09) and a lower ground ball rate (48.8 GB%, 54.2 GB% in ’09). No, he hasn’t been six-plus ERA bad — his BABIP (.350) and strand rate (61.6%) will regress toward the mean — but Porcello’s xFIP has climbed to 5.14 in 2010 after coming in at 4.32 in 2009.

At this point, Porcello basically has one pitch going for him: a 90 MPH sinker that he throws for strikes and uses to get grounders. Everything else is a work in progress. His four-seamer, thrown a couple ticks quicker, has a decent whiff rate, but Porcello struggles to locate it. Hitters lay off his lackluster breaking and off-speed stuff:

Having thrown all of 125 innings in the minors, Porcello is learning on the job. And he’s still got a ways to go.

Chase Headley, Padres

A full-time third baseman after spending the better part of the past two seasons in left field, Headley is flashing the leather — he has a +8.1 UZR/150 at 3B. His bat lags behind, however.

It seems like the switch-hitter might be trying to make more contact, to the detriment of his power and overall offensive performance. During his rookie season in ’07, Headley struck out 31.4%, with a 72.7 Contact%. Last year, he whiffed 24.5% and made contact 77.8%, and this season he’s punching out 20% with an 81 Contact%. His ISO over that time frame has dipped from .151 to .131 to .093. Headley’s wOBA has declined three years running as well, going from .334 in 2008 to .328 last year to .305 in 2010.

Considering that he’s not drawing many walks this year (5.7 BB%) while just blooping some singles, it’s not surprising that Headley’s offense has been below-average even after accounting for cavernous Petco Park — his wRC+ is 95.

Chris Tillman, Orioles

Tillman, 22, has fantastic long-term potential. He was ranked as a top 100 prospect by Baseball America prior to the 2008 and 2009 seasons, and he has 8.5 K/9, 2.2 BB/9 and a FIP around three in 154.1 innings at the Triple-A level over the past two years. Past scouting reports lauded his low-90’s heat (peaking around 94 MPH) and above-average curveball, delivered from a lanky 6-5 frame.

In the majors, however, Tillman’s stuff hasn’t looked as sharp. Tossing 15 innings for the O’s this year, Tillman has a 7/8 K/BB ratio, with 15 runs surrendered. His average fastball velocity is slightly under 91 MPH. In 80 combined IP over the past two years, Tillman has 5.18 K/9, 3.6 BB/9 and a 5.31 xFIP. Both his four-seam fastball and curve have below-average whiff rates in the bigs so far (4.6% and 7.5%, respectively), which helps explain the lack of K’s. As an extreme fly ball pitcher (36.5 GB% in the majors, 39.7 GB% in the minors), Tillman needs to miss more bats and display sharper control. There’s nothing alarming here long-term, but Baltimore could send him back to Triple-A to work out the kinks.

Glance at Clay Buchholz’s ERAs over the 2008-2010 seasons, and you’ll be inclined to believe that the former phenom’s major league performance has progressed from ghastly (6.75) to good (4.21) to great (2.52). That’s a compelling narrative — the hot-shot prospect tosses a no-no during a September ’07 call-up, gets his head handed to him the following year and then makes the necessary adjustments to blossom into a full-fledged ace.

It’s a nice story. But it’s also misleading. In truth, Buchholz neither fell to the depths of despair that his ’08 ERA suggests, nor has he risen from the ashes like a phoenix this season for a Boston rotation suffering greatly from injury and underachievement. Throughout his big league tenure, Buchholz has been pretty good, but hardly elite.

In 2010, Buchholz has 5.72 K/9, 3.78 BB/9, a 51.5 percent ground ball rate and a 4.33 xFIP in 78.2 frames. For comparison, his xFIP was 4.28 in ’08 and 4.09 last season. The big change in Clay’s ERA is due to factors largely out of his control — his BABIP is .268 (.302 career average) and his home run per fly ball rate is just 4.2%. His career rate is 11%, right at the big league average.

The 25-year-old’s K rate is down from the previous two seasons (8.53 K/9 in ’08, 6.65 in ’09). His swinging strike rate is basically the same all the years, ranging from 9.7% to 9.9% (8-9% MLB average), but the culprit for the lack of punch outs appears to be the rate of contact made against Buccholz’s pitches thrown outside of the strike zone. He’s throwing more off-the-plate pitches in 2010, and batters are swinging at plenty of them. But they’re also connecting more often against those offerings:

Buchholz has thrown just 43.8 percent of his pitches within the zone this year (47.3% MLB average). Batters have gone after his out-of zone pitches 31.5% (28.1% MLB average). However, they have put the bat on the ball 67.6% (66.4% MLB average).

That’s a sizeable increase from the previous two seasons — in 2008 and 2009, hitters made contact with Buchholz’s out-of-zone pitches at a rate that was about seven percent below the major league average. This season, they’re making contact on those pitches at a clip that’s two percent above the MLB norm.

Pitch selection has played a role in the K decline. Buchholz has a four-pitch mix: a 93-94 MPH fastball, a hard-upper 80’s slider, a mid-to-high-seventies curveball and a 79-80 MPH changeup. According to Pitch F/X data from Trip Somers’ site, Buchholz has increasingly gone to his slider this season, at the expense of some changeups and curves:

His fastball has never garnered many whiffs, and neither has his curve. Buchholz’s changeup has always gotten a healthy number of swing-throughs. His slider produced plenty of whiffs in ’08, but it’s not missing many bats this year:

So more sliders, and fewer whiffs on the slider. In our splits section on the player pages, we have pitch usage by count. Buchholz is going to his fastball and slider (two pitches with below-average whiff rates) more often in two-strike situations, in place of his curveball and whiff-generating changeup:

(note: the numbers are rounded, so not all columns add up to exactly 100).

These changes in Buchholz’s approach help explain why he hasn’t missed as many bats as expected. His minor league K rates suffered over this period as well. Buchholz spent much of 2007 pitching between Double-A Portland and Triple-A Pawtucket, and he logged a good number of innings with the PawSox in ’08 and ’09. Buchholz’s major league equivalent K rates declined over the years — According to Minor League Splits, Buchholz’s work in the minors in 2007 translated to 9.8 K/9 in the big leagues, but that mark fell to 7.7 K/9 in 2008 and 6.7 K/9 in 2009.

Clay Buchholz has a fantastic minor league track record. He exhibits strong ground ball tendencies, and he was an elite strikeout pitcher during most of his days as a prospect. It wouldn’t be surprising if he took significant steps forward in the coming years. But the current version of Buchholz is more of a solid, low-four’s ERA-type than any sort of rotation messiah.

Jonathon Niese (owned in 6% of Yahoo leagues)

Niese, 23, cobbled together a quality minor league resume (8.2 K/9, 3.1 BB/9, 51.8 GB%). The left-hander was on his way to establishing himself as a member of the Mets’ rotation last season when a torn right hamstring ended his season in August, requiring a surgical fix. He hit the DL this season with another, milder right hamstring injury. But when on the mound, Niese has impressed.

Tossing 57.1 innings, New York’s seventh round pick in the ’05 draft has 7.06 K/9, 2.98 BB/9 and a 3.94 xFIP. He’s showing strong a ground ball rate to boot, with a 52.2 GB%. Niese doesn’t blow batters away — his fastball hits 90 MPH on a good day. But he supplements the pitch with a mid-80’s cutter that tails in on the hands of righties, as well as the occasional mid-70’s curveball and low-80’s changeup. Niese’s four-seamer and cutter both have above-average strike and whiff percentages:

Four-Seamer: 66.2 Strike% (64.1% MLB Avg.), 8.1 Whiff% (6% MLB Avg.)
Cutter: 69.4 Strike% (68.3% MLB Avg.), 12 Whiff% (8.8% MLB Avg.)

For the rest of 2010, ZiPS projects 6.53 K/9, 3.36 BB/9 and a 3.93 FIP from Niese. He doesn’t possess one standout skill, but Niese makes batters chop the ball into the grass while amassing decent K and walk rates. He’s plenty useful in NL-only formats.

Troy Glaus, Braves (63%)

Signed to a one-year, $1.75 million deal over the winter, Glaus was picked up off the scrap heap as a Freddie Freeman stopgap. The former Angel, Diamondback, Blue Jay and Cardinal’s career looked to be on the ropes after a 2009 season ruined by a back problem and a right shoulder injury that required surgery. CHONE (.249/.359/.447, .356 wOBA) and ZiPS (.252/.358/.441, .355 wOBA) projected a reasonably productive season for Atlanta’s reclamation project, but that was under the assumption that the 33-year-old wouldn’t again fall to pieces physically.

So far, Glaus has stayed healthy and is surpassing those pre-season forecasts. In 253 plate appearances, he has a .279/.375/.474 line and a .373 wOBA. He’s drawing walks at a 13.4% clip, and while he’s not hitting for the mammoth power of years past, Glaus has a solid .195 ISO. Freeman (.249/.306/.422 in 185 AB in Triple-A) isn’t exactly tearing the cover off the ball for Gwinett, so Glaus’ job looks secure. ZiPS projects a .260/.363/.449 triple-slash from here on out, with a .361 wOBA.

Pittsburgh Pirates recalled OF Jose Tabata from Triple-A Indianapolis.

Tabata, 21, is a polarizing prospect. His backers see a precocious talent who makes score of contact and possesses more athleticism than one would expect from his compact frame. Those more skeptical of Tabata’s upside point out uncertainty about his age and limited power potential.

Signed by the Yankees out of Venezuela for $550,000 in 2004, Tabata burst on to the prospect scene by showing an exciting blend of hitting skills and speed in A-Ball over the 2006 and 2007 seasons. As a 17-year-old in the Low-A South Atlantic League, he hit .298/.377/.420 in 363 plate appearances. He had decent strike zone control (8.3 BB%, 20.7 K%) and a pinch of power (.122 ISO), while swiping 15 bases in 20 attempts. In the High-A Florida State League in ’07, Tabata had a .307/.371/.392 triple-slash in 456 PA. He walked 7.3%, punched out 16.9% and had a .086 ISO, going 15-for-22 on the base paths.

Those numbers don’t stand out at first glance, but are more impressive when the context is considered. Tabata was (apparently) the same age as high school sophomore in ’06 and a junior in ’07, and the FSL is a pitcher-friendly circuit. Baseball America rated Tabata as the 27th best talent in the minors prior to 2007 and the 37th-rated prospect leading up to 2008.

That ’08 season wouldn’t be a banner one for him, though. Bumped up to Double-A, Tabata posted feeble numbers at the plate, angered the Yankees by leaving the park during an April game and tweaked his hamstring. He was shipped to Pittsburgh (along with Ross Ohlendorf, Daniel McCutchen and Jeff Karstens) that July for Xavier Nady and Damaso Marte. Tabata picked up the pace in the Eastern League after the trade, finishing the season with a .277/.345/.388 line in 442 PA. He walked 8.1%, struck out 17% and had a .111 ISO, with 18 SB and two CS. BA knocked him down its list somewhat, but Tabata still cracked the top 100 (#75).

Last year, the 5-11, 210 pound righty batter began the year back at Altoona. Though he was caught red-handed on the bases often (7 SB, 6 CS), Tabata hit .303/.370/.404 in 254 PA. His secondary skills were again mild (7.9 BB%, .111 ISO), but he punched out just 11% of the time.

Tabata was promoted to the Triple-A International League later that summer, and that’s where he opened 2010 as well. In 400 combined PA at the level, he owns a .296/.358/.419 line, with an 8.3% rate of free passes taken, a 14.8% K rate and a .123 ISO. Happily for fantasy folks, Tabata has recovered his base stealing prowess (29 SB, 8 CS, a 78.4% success rate).

Assuming the right hamstring cramp he suffered last night isn’t serious, Tabata figures to see a lot of playing time — Jeff Clement has been banished to Triple-A, and Garrett Jones will man first base more frequently.

His long-term value is hard to gauge, however. Is Tabata 21? Not even the Pirates seem to know for sure. Will he ever hit more than the occasional double? He doesn’t have a projectable frame, as he’s under six feet and has already filled out physically. Will his stolen base totals translate to the highest level? Tabata’s not a speed demon, with tick-above-average wheels. There are a wide range of possibilities here.

Tabata’s someone to watch in NL-only leagues, and he has some value in keeper formats. But keep in mind that there are a plethora of potential outcomes — he could be anything from a 21-year-old with room to develop offensively to a maxed-out 24-year-old who needs to play plus defense to be worthy of an everyday spot in the lineup.