Brennan Boesch Mashing

On April 23rd, Brennan Boesch stepped into a major league batter’s box for the first time and proceeded to rip the first Rich Harden offering he saw for a double. Since then, the 25-year-old Tigers rookie hasn’t stopped swinging or making loud contact. In just 74 plate appearances, Boesch’s bashing has been worth +7.4 park-adjusted Batting Runs. Where did this guy come from, and what can we expect from him going forward?

Detroit snagged Boesch out of California in the third round of the 2006 draft. A 6-4, 235 pound lefty batter, Boesch fit the physical description of a power hitter but confused scouts with uneven performances for the Golden Bears. Here’s Baseball America’s scouting report leading up to the draft:

He has what scouts look for in a prospect, but while he had set a new career high with 10 home runs, his slugging percentage was actually lower than it was in 2005, and scouts had been disappointed by his overall performance. He’s been erratic, at times showing above-average bat speed and the ability to catch up to good fastballs, and at others showing a long swing that short-circuits his power. His hands are dead at the start of his swing, often keeping him from loading up and generating power.

The Tigers sent Boesch to the short-season New York-Penn that summer, where he hit .291/.344/.435 in 317 plate appearances. He walked in 6.6 percent of his PA and punched out 14.4 percent, posting a .144 Isolated Power.

Boesch ranked 16th on BA’s list of top Tigers prospects prior to the 2007 season, but he dipped to 24th before 2008 and fell off the list entirely leading up to the 2009 campaign. In the Low-A Midwest League in ’07, he batted a weak .267/.297/.378 in 542 PA, drawing ball four 4.2 percent and striking out 15.8 percent. Boesch’s ISO fell to a middle infielder-like .111, with BA saying that he “lacked the plus power expected from a corner outfielder.”

His 2008 season was little better: a .249/.310/.379 triple-slash in 461 PA in the High-A Florida State League, with a 7.8 percent walk rate, a 21.6 percent K rate and a .129 ISO. The MWL and the FSL are difficult offensive environments, but college-trained outfielders hacking and hitting singles aren’t going to elicit much excitement from talent evaluators.

In 2009, Boesch showed an offensive pulse for the first time in pro ball. Bumped up to the Double-A Eastern League, he hit .275/.318/.510 in 571 PA. Boesch remained aggressive (5.8 BB%) and his strikeout rate climbed to 24.1 percent, but his ISO shot up to .235. Baseball America rated Boesch as the 26th-best prospect in Detroit’s system this past offseason.

After a hot start in the Triple-A International League (.379/.455/.621 in 66 PA), Boesch got the big league call and has logged time in the corner outfield and DH spots. He owns a .380/.392/.676 line, with three home runs and a .296 ISO. Boesch’s plate approach, however, leaves much to be desired.

So far, his strike zone has been the size of Lake Michigan. Boesch has chased 50.4 percent of pitches thrown outside of the zone, highest among hitters with at least 70 plate appearances. He’s out-hacking the master of junk ball swinging, Vladimir Guerrero (49.6 O-Swing%). On pitches within the zone, Boesch has taken a cut 84.6 percent. Only Vlad (86.4 Z-Swing%) has swung at in-zone pitches more often. Boesch’s overall 66.4 percent swing rate bests The Impaler’s 65.2 percent mark.

Guerrero might be able to get away with swinging at everything. Boesch isn’t Vlad, though. That 2.7 percent walk rate is going to be an issue once his .421 batting average on balls in play comes back down to Earth.

Coming into 2010, CHONE projected Boesch for a .230/.261/.364 line. That seems pessimistic, but it is important to keep in mind that we’re talking about a mid-twenties prospect with a career .273/.319/.434 minor league line. He has an ultra-aggressive philosophy, and holds a .247/.294/.364 minor league triple-slash against lefty pitching. Boesch isn’t a hot-shot youngster so much as he’s a righty masher with a low OBP and problems with same-handed hurlers.