Brian already took a look at ten hitters who improved in May after subpar Aprils, so now let’s do the same with the guys on the mound.

Scott Baker

A: 4.28 xFIP
M: 3.67

Amazingly, Baker’s batted ball data was practically identical in the season’s first two months, but he beefed up the strikeouts (7.82 K/9, up from 6.35) and cut down the walks (1.89 BB/9, down from 2.54). The result was a 3.55 ERA that’s much more indicative of his true performance than his 5.72 April mark. (R) ZiPS sees a 3.88 FIP and 7.00 K/9.

Chad Billingsley

A: 4.36 xFIP
M: 3.50

The ace version of Billingsley showed up in May, flashing an 8.77 K/9 and a 2.31 BB/9, which are much better than what we’ve seen out of him over the season’s first month and the end of last year. (R) ZiPS calls for a 3.49 FIP with 8.60 K/9.

Jeremy Bonderman

A: 4.43 xFIP
M: 3.65

Still just 27, Bonderman might have a big second half contract push in him. The K/9 and BB/9 both improved by more than one in May. (R) ZiPS sees a 4.42 FIP and 6.50.

Johnny Cueto

A: 4.87 xFIP
M: 3.21

Sure, his .244 May BABIP is low, but he increased his K/9 by more than four strikeouts (up to 9.79) and knocked more than a full walk off his BB/9 (down to 1.85). (R) ZiPS projects a 4.17 FIP with 7.62 K/9.

Aaron Harang

A: 4.16 xFIP
M: 3.62

The Harangatang hasn’t been himself for over a year now, but he still has strikeout value. Once he starts stranding more than 6% of the runners that reach base, his 5.48 ERA should start to resemble his defense-independent numbers. His homerun rate returned to normal in May, which is always welcome. (R) ZiPS projects a 4.12 FIP and 7.51 K/9.

Rich Harden

A: 6.82 xFIP
M: 4.63

Yeah, he’s the least economical pitcher in the game at 19.7 P/IP (one-tenth of a pitch ahead of Charlie Morton!), but he stopped walking everyone and their mother last month: his BB/9 rate went from an ungodly 8.75 to a much more reasonable 3.91. (R) ZiPS projects a 4.10 FIP with 9.78 K/9.

Edwin Jackson

A: 4.28 xFIP
M: 3.63

Jackson won’t return to first half of 2009 levels anytime soon, but his strikeout rate jumped up from 5.40 K/9 in April to 9.60 in May, and his BABIP fell back to a more reasonable level (.305). Not all the way there yet, but it’s progress. (R) ZiPS predicts a 4.32 FIP and 6.98 K/9.

Jake Peavy

A: 5.84 xFIP
M: 3.03 xFIP

The former Cy Young Award winner’s ERA was still bad this month (5.09), but Peavy’s K/9, BB/9 and GB% went from 6.91, 6.28, and 31.5% in April to 8.85, 1.11, and 48.3% in May, respectively. He’s not quite there yet, but at least there’s signs of improvement. (R) ZiPS calls for a 3.89 FIP and 8.69 K/9.

Ervin Santana

A: 4.12 xFIP
M: 4.00

The strikeouts climbed to 8.44 K/9, the walks dropped to 2.32 BB/9, and the homerun rate leveled off at 10.0% HR/FB. The (R) ZiPS survey says … 4.10 FIP and 7.98 K/9.

Ben Sheets

A: 5.35 xFIP
M: 3.92

Apparently everything that was wrong with Sheets in April was corrected in May when the A’s realized he was tipping his curveball. Sure enough, his K/9 (9.42) more than doubled last month, and the rest of his peripherals look more like the Ben Sheets we all know and love. (R) ZiPS predicts just 4.31 FIP with 6.24 K/9. I’ll take that bet.

Here are seven players for your consideration to either acquire or send packing.

BUY

Dan Haren – One of the top 10 pitchers off the board in most fantasy drafts, Haren has produced a -$3 fantasy value this year according to Last Player Picked. On top of that, Haren is known as a first-half pitcher, as his ERA is nearly a full run higher after the All-Star break and his WHIP goes from 1.085 to 1.316 in the second half of the year. But Haren has been one of the unluckier pitchers around, with a .342 BABIP and a 17.0 HR/FB rate. His GB/FB ratio is nearly identical to where it was a year ago and Haren’s K/BB ratio of 5.53 is the second-best mark in baseball.

Juan Rivera – His ownership rate in CBS Sports leagues has declined from 77 percent on Opening Day to just 45% this week. Rivera got off to a slow start in April and did even worse in May. But Rivera had just a .203 BABIP last month. With Kendry Morales on the shelf, there are no worries about Rivera not getting the playing time to work out of his slump. He is likely available for little cost and could provide a nice HR bump going forward. And with a little better luck on balls in play he could prove not to be an anchor in AVG, either.

David Wright – Current owners may look at his .353 BABIP and .269 AVG and decide that Wright is no longer an elite fantasy player. Certainly, the 35.5 K% is troubling to everyone. But Wright’s HR power is back from its 2009 vacation, as his 16.4 HR/FB mark is nearly 10 percent higher from a year ago and right in line with the numbers he produced from 2004-2008. (U) ZiPS sees him getting the same 27 SB he did a season ago. So the big question is: How will Wright do in AVG here on out? A plethora of Ks killed his AVG through most of May, but Wright seems to be getting on track recently. In the tiny sample of eight games, Wright has 6 Ks in 29 ABs and a .310/.382/.517 slash line. In his previous 21 games, Wright fanned in 34 of his 80 ABs and posted a .250 AVG. If Wright can keep his strikeouts down to his career level of 20.9 percent, he is a good bet to challenge for .300 going forward.

SELL

Elvis Andrus – Despite a .267 AVG last year, Andrus excited fantasy players with his ability to steal bases. (U) ZiPS shows him finishing the 2010 season with 43 SB, which would top all of the preseason projections for him. Andrus is also projected to smash the preseason predicitions with 92 R, thanks in part to his move to the top of the order. But now is the time to sell high on the Rangers’ shortstop. His .380 BABIP screams regression. (R) ZiPS sees a .318 mark here on out and even that might be optimistic. As a GB hitter with good speed who can hit line drives, Andrus profiles as a player who would post a high BABIP. But last year he had a .305 mark in 541 PA.

Matt Garza – A four-category contributor on the first-place Rays, Garza is ready to challenge for career-bests in each fantasy category. But his K/9 is down from 8.38 a year ago to 7.11, his GB/FB ratio is a career-low 0.84 and he has a .266 BABIP. Garza has consistently posted low HR rates, so his FIP might be a better marker than xFIP, but both of those metrics are a full run above his current 3.08 ERA.

Andy Pettitte – The Yankees ace just keeps rolling along and is on pace for a 20-win season for the first time since 2003. But (R) ZiPS sees his production from here on out falling off significantly. And given Pettitte’s age (38 in June), xFIP (4.09) and injury concern, that projection should be taken seriously. Pettitte missed a start in early May due to elbow inflammation. In four starts since returning, he has a 3.08 ERA and a 4.85 K/9.

HUNCH

Torii Hunter – Last season Hunter was enjoying a career year before ending up on the DL with a groin injury which cost him 39 games. This year Hunter got off to a solid start in April but scuffled in May. After pounding fastballs last year, Hunter is below-average against them this season. I like Hunter to recapture the magic from last year and exceed his (U) ZiPS projection of .278-21-83-77-12.

It’s now summer by the American social clock (if not by the solstice calendar), and so you should be furiously checking your wire for injury replacements. It’s even time to start considering if a struggling player is ready to be dropped. We’re here to help.

Brett Myers, Astros (10% owned)
Myers is a flawed pitcher. He may never again reach the strikeout-per-inning numbers of his early career, and he’s lost some velocity off of those days as well. The good news is that the fastball was never his best pitch – in fact, it’s never even been a good pitch (-89.6 runs career, and never once positive by linear weights). He’s still got his nice curveball and slider, and he’s actually snapping that slider at a career pace (32% this year, 9.6% career). This will count as good news because not only is the pitch his best this year (+6.6 runs), but it’s also been his best non-curveball pitch in his career. If this ‘new’ Myers can stay healthy, he seems likely to continue to pitch to the talent level indicated by his 3.89 FIP. Flawed, but helpful in deep leagues. When his .324 BABIP comes down a little bit, his poor WHIP might even improve.

Cliff Pennington, Athletics (11% owned)
Here’s another flawed player for your pleasure. In fact, it’s possible he’s over-owned for a shortstop with an underwhelming .209/.291/.322 line. Of course, his BABIP is .245 and should rise, especially since he’s relatively fleet of foot (5.6 career speed score, six stolen bases this year). In other good news, his contact rates are all up across the board, and his zone contact rate (93.4%) is actually okay. His good line drive rate (21.4%) suggests that he may even be able to better his ZiPs RoS (.250/.324/.348) and break 20 steals overall. If someone in your AL-only league dropped him, he can give you a little something from here on out. Just a little.

Jerry Hairston Jr, Padres (5% owned)
Boy, hit one grand slam and suddenly you’re on waiver lists, eh? Of all the numbers that we may cite about Hairston, however, there is one that is the most important once you get into deep enough leagues: seven. As in, Hairston has started seven straight games for the Padres. This, despite Everth Cabrera’s return from the disabled list. Hairston’s defense is scratch at best (-7.9 UZR/150 in 109 career games at the position), but right now his offense is perculating (10 for his last 26) and the team is winning. And anyway, it’s not like Cabrera was a whiz with the glove anyway (-11 UZR/150 in 127 games at the position). The Padres might best be served being honest about the talent level on their team, and going with the guy that could provide more value for longer in Cabrera, but that’s an argument for another space.

All ownership numbers courtesy of Yahoo Fantasy Sports

Last month, we took a gander at starting pitchers who had significant differences between their respective ERAs and xFIPs. xFIP, based on strikeouts, walks and a normalized home run per fly ball rate, does a better job than ERA of gauging performance in the areas over which pitchers have the most control. It’s not subject to more luck-based factors such as batting average on balls in play, strand rate and home runs per fly ball hit.

Now that another month has passed, let’s update the ERA-xFIP lists for the 2010 season. Here are the 20 starters whose ERAs are far lower than their xFIPs (minimum 30 IP for the season):

In general, you’ll note very low BABIPs and home run rates, as well as high rates of stranding runners on base.

As mentioned last time, an appearance on this list does not make a pitcher “bad” or a “fluke” — there are plenty of useful starters here, and at least one elite arm. However, looking at the ERA-xFIP split can make owners view big “breakouts” from the likes of Niemann, Cahill, Buchholz, Pelfrey, Garza and Sanchez with a more skeptical eye. Zito, Fister and Garland are generating more grounders, pitch in front of quality defenders and reside in pitcher’s parks, but those shiny ERAs are going to rise.

And here are the 20 starters whose perhipherals suggest better days are ahead:

This is basically the flip side of the previous list — very high BABIPs and home run rates, and low strand rates. Haren (profiled here), Beckett, Masterson (expect a post on him later this week) and Harang (ditto) stand out here. Jackson isn’t really pitching much differently than he did with Detroit last year, and Peavy isn’t that far off realistic expectations, once you account for his pitching in the DH league in a hitter’s park.

One of the hardest things to do is know when it is time to cut loose a player who is struggling in the month of April. Here are 10 batters who rewarded the faith of the owners who kept them, or the foresight of the owners who traded for them, with big comebacks in the month of May.

Jose Bautista
A – .213-4-16-12-2
M – .287-12-25-25-1

Sure, he only has a .238 BABIP this season. But a .350 ISO covers up a lot of other ills. (R) ZiPS sees him hitting .232 with 14 HR.

Troy Glaus
A – .194-2-9-8-0
M – .330-6-28-17-0

He looked like a candidate to be released the first month of the season. Fortunately for him, top prospect Freddie Freeman did not get off to a hot start. Glaus proceeded to hit like it was the year 2000 in May. (R) ZiPS projects him hitting .261 with 11 HR.

Jonny Gomes
A – .217-2-12-9-0
M – .364-5-22-16-1

He is seeing time against both lefties and righties. Gomes still mashes LHP (.466wOBA) and is holding his own (.322 wOBA) against RHP. (R) ZiPS predicts a .257 AVG with 14 HR.

Vladimir Guerrero
A – .333-2-13-11-3
M – .330-10-31-18-1

At the end of April everyone was worried about Guerrero’s power. Then in May he delivered the power while keeping the high AVG. (R) ZiPS sees a .310 AVG with 17 HR.

Corey Hart
A – .270-3-11-5-2
M – .253-10-22-16-1

While his AVG declined in May, Hart had an explosion in HR-RBI-R to merit inclusion on this list. Hart had a .217 BABIP in May but was saved by his HR output. In the just completed three-game set against the Mets, Hart went 3-12 and all three hits were HR. (R) ZiPS forecasts a .263 AVG and 15 HR.

Mike Napoli
A – .167-0-2-2-1
M – .322-8-17-15-2

He slugged like a first baseman during May and now with the injury to Kendry Morales, Napoli might get some playing time at that position. (R) ZiPS projects .262 AVG and 13 HR.

David Ortiz
A – .143-1-4-5-0
M – .363-10-27-16-0

After combining for 1 HR in April and May last year, Ortiz went on to hit 27 HR the rest of the year. Another slow start in April had many writing Ortiz off, but he responded with his best month since September/October of 2007. (R) ZiPS predicts a .263 AVG and 20 HR.

Alex Rios
A – .277-3-9-10-9
M – .344-8-18-22-7

Could become the first player released in one season to go 30-30 the following year. (R) ZiPS sess a .281 AVG and 15 HR which would leave him 4 HR shy of 30.

Nick Swisher
A – .250-2-11-10-0
M – .374-7-17-24-0

Coming into this season, Swisher’s career-high in BABIP was the .301 mark he posted in 2007 with the Athletics. After two months of the season he has a .376 mark, the 10th-best in the majors. (R) ZiPS forecasts a .258 AVG and 17 HR.

Mark Teixeira
A – .136-2-9-11-0
M – .280-6-25-22-0

One of the most consistent slow starters in baseball did nothing to change that perception this April. Teixeira has a lifetime .753 OPS in April compared to a .914 OPS overall. But (R) ZiPS does not project a massive comeback as it has him down for a .269 AVG with 19 HR going forward.

Ryan Zimmerman, Nationals

During the first three full years of his major league career, Zimmerman combined fantastic D with an above-average bat — his wRC+ from 2006-2008 was 110. Since then, the fourth pick in the 2005 draft has kept the slick leather and improved his lumber. He posted a 132 wRC+ in 2009 and holds a 160 wRC+ in 2010.

Zimmerman’s power production has soared, with his Isolated Power figures going from the high 100’s to .233 in ’09 and .295 this season. ISO tends to become reliable around 550 plate appearances, and Zimmerman has been hitting for elite pop for nearly 900 PAs now. His rest-of-season ZiPS calls for a .289/.361/.522 triple-slash, with a .233 ISO. Remember Scott Rolen’s peak? Zimmerman, 25, is now that type of player.

Phil Hughes, Yankees

Though he has seemingly been a topic of conversation for years, Hughes turns just 24 this month. And he has been great as a starter — in 56.2 frames, he has 9.05 K/9, 3.02 BB/9 and a 3.63 xFIP. The 6-5, 240 pound right-hander is doing a great job of getting ahead in the count, with a 67 first pitch strike percentage (58% MLB average), and he’s getting batters to chase out of the zone 34.8% (27.8% MLB average). That’s the sixth-highest chase rate among MLB starters tossing at least 40 innings.

How is Hughes getting the job done? With 92-93 MPH fastballs and high-80’s cutters that hitters can’t seem to lay off. The 2004 first-rounder has gone to his fastball about 52 percent, getting a strike 70.2 percent of the time (64.4% MLB average) and getting a whiff 9.3% (6% MLB average). Batters have offered at the four-seamer 51.9 percent (45.2% MLB average).

The cutter, used about 27 percent of the time, has been thrown for a strike 75.1% (66.7% MLB average). It’s getting whiffs 10.4% (8.4% MLB average) and has been swung at 63.1% (50% MLB average). Hughes’ curve isn’t faring as well, with below-average strike, whiff and swing rates, but the fastball and cutter have made him death on righties (2.88 xFIP) and acceptable against lefties (4.40 xFIP).

If Hughes is still available in your league, well, what are you waiting for? ZiPS projects 8.51 K/9, 3.02 BB/9 and a 3.68 FIP from here on out. The Yankees are going to be cautious with his workload, but he’ll continue to deal when he’s on the mound.

Ryan Doumit, Pirates

The 29-year-old switch-hitter has a Tolstoy-length injury history — a torn hamstring in 2006, a concussion as well as a wrist and ankle sprain in 2007, a fractured thumb in 2008 and a wrist injury that required surgery in 2009 — but when he’s not hurting, he’s mashing.

After posting a 126 wRC+ during a (moderately) healthy 2008, Doumit’s production dipped considerably in 2009 (85 wRC+). Some of that was poor luck on balls put in play, but he hacked at a career-high 33.2% of pitches thrown outside of the zone.

In 2010, Doumit has chased 24.2% of off-the-plate pitches, and he’s drawing walks at a career-best 10.3% clip. His first pitch strike percentage is just 44.6 — that’s lowest among MLB batters with at least 100 trips to the plate. Doumit has a 127 wRC+ in 175 PA, with a .281/.371/.451 line. ZiPS projects a .277/.339/.458 showing for the rest of 2010, which is plenty useful for a backstop. But if Doumit continues to work the count well, his value gets a boost.

Of course, all of this is assuming he doesn’t hit the DL tomorrow.

Akinori Iwamura, Pirates

Picked up from Tampa Bay over the off-season for RHP Jesse Chavez (who was subsequently sent to Atlanta for Rafael Soriano), Iwamura has effectively lost the starting gig at the keystone spot for Pittsburgh to Neil Walker.

CHONE (108 wRC+) and ZiPS (107 wRC+) both forecast Iwamura for a solid offensive season, getting on base at a characteristically high rate while displaying little pop. Instead, Aki has a 49 wRC+ in 181 PA. He’s drawing a walk 12.1% of the time, but an incredibly low BABIP has made him one of the worst players in the majors to date.

During his major league career, Iwamura has a .330 BABIP. CHONE projected a .343 pre-season BABIP, and ZiPS .345. Aki’s 2010 BABIP? .198. He has had fewer batted balls classified as line drives (13.3%, compared to a 19.4% career average), and his ground ball rate has spiked to 58.6% (47.3% career average). That helps explain why his ISO is .076, below his pre-season projections of .109 from CHONE and .114 from ZiPS, as well as his career .108 mark.

Those aren’t promising developments, but Iwamura probably hasn’t totally lost it — his rest-of-season ZiPS projection is .262/.337/.369, with a .319 wOBA. Even so, the Pirates’ decision to give Walker (profiled here) a shot is defensible. The 24-year-old has a .262/.307/.449 rest-of-season ZiPS. It remains to be seen how he’ll handle second base, and he’s no top prospect these days. But Walker could be part of the next relevant Pirates team, while Iwamura won’t be.

Daisuke Matsuzaka, Red Sox

Since returning from a neck/back strain, Matsuzaka has been a pain in the neck to Sox fans and fantasy owners alike. Dice-K has 6.55 K/9, 5.5 BB/9 and a 5.49 xFIP in 34.1 innings pitched. He has put 46.4% of his pitches within the zone (47.5% MLB average), and he’s getting first pitch strikes just 52.4%. Matsuzaka also isn’t missing bats — his swinging strike rate is 6.4%, compared to the 8-8.5% MLB average and his career 9.7% average.

During his first two seasons state-side, Dice-K was basically a league-average starter (4.31 xFIP in 2007, 4.70 in 2008). He was control-challenged, but at least compensated with good K rates. Last year’s shoulder ailment and 4.83 xFIP, coupled with more injury concerns and lousy pitching this season, make him hard to recommend. The upside here would appear to be a 4.25-4.50 ERA. Is that worth all the aggravation?

Gordon Beckham, White Sox

Beckham went from Athens to the South Side in short order, putting up a .270/.347/.460 triple-slash and a 112 wRC+ in 2009. CHONE (115 wRC+) and ZiPS (111 wRC+) predicted more of the same for the 23-year-old, and Beckham’s value received an extra boost fantasy-wise with his shifting from third to second base.

Flash forward two months into the 2010 season, and Beckham is owned in just 42% of Yahoo leagues. He has a ghastly .196/.286/.239 line in 187 PA, with a 45 wRC+.

It would be rash to sell low on Beckham in keeper leagues, as he remains a valuable long-term talent, but he looks lost at the plate at the moment. After swinging at 24.8% of out-of-zone pitches during his rookie year, Gordon has gone fishing 30.6% this season. His groundball rate is up 10 percentage points (40.4% to 50.4%), and his pop up rate has increased — 14%, compared to 11.9% last year and the 7-8% big league average. Beckham’s .043 ISO puts him in the illustrious company of Jason Kendall and teammate Juan Pierre.

He’s not going to keep a .238 BABIP, but Beckham is surely testing the patience of owners who have stuck with him through his struggles.

We already discussed Buster Posey’s arrival over the weekend, but here’s two more recent call ups that could help your team…

Andrew Cashner | Cubs | RP

The Cubs’ first round pick in 2008 made quick work of the minor leagues this year, posting a 59/15 K/BB ratio in 57 IP as a starter (~2.15 FIP) between Double- and Triple-A. The big league team needed some righthanded relief help with Carlos Zambrano moving back into the rotation, so for the second time this year the Cubbies called on their top minor league prospect to fill a hole. Cashner debuted yesterday, getting Ronny Cedeno to pop up to short on just one pitch (a 95 mph fastball inside) with two men on and two outs in the 8th inning with Chicago trailing by one. It was about as spectacular as a one-pitch big league debut could be.

Now Cashner’s not going unseat Carlos Marmol as closer as long as the latter continues to strike out basically half the men he faces, but he could quickly push his way into some 7th and 8th inning setup work. Close to a strikeout per inning with a sub-4.00 ERA is likely, so if your league counts holds, here’s a new candidate to consider.

Chris Tillman | Orioles | SP

If you’re going to pick up an Orioles’ starter, you have to go in expecting very little help in the win column. Kevin Millwood is having his best season in about four years (4.00 xFIP, 3.41 K/BB), but he’s got an 0-5 record to show for it. Tillman and Brian Matusz are the future of Baltimore’s rotation, but right now they’re just 6th or 7th starters on a fantasy roster. ZiPS RoS projection for Tillman isn’t good – 5.13 ERA, 4.67 FIP – but I think he can best those numbers. Maybe I’m just a blind optimist, but I think he can keep his walks around 3.5 BB/9 and his strikeouts around 7.5-8.0 K/9 (both in line with his career Triple-A performance), which should put his ERA in the low-to-mid 4.00’s assuming a somewhat normal homerun rate.

The AL East is an unforgiving place, especially when you play for a generally awful team, so Tillman only has value in deep mixed or AL-only leagues. His next two starts come at home against the Red Sox and Yankees, but after that he lines up for dates in San Francisco, in San Diego, at home against the Nats, and at home against the A’s. Not a bad stretch of matchups, so there’s a little bit of value to be had this month.