June 28, 2010
The 3rd-highest TAv (.339) in the American League belongs to a player with a.225/.269/.372 weighted-mean projection. PECOTA was so pessimistic about his prospects that even his 90% projection called for a sub-replacement performance; for added insult, his ten-year forecast banished him below replacement-level through 2019.
How many of you had heard of Brennan Boesch three months ago? After only two months in the majors, the mysterious man from the first paragraph has already put 4 wins’ worth of distance between him and the replacement player we projected him to trail. In BP2010, we wrote that Boesch had “a swing more hole-y than the Pope and a swing-at-anything approach less discriminating than Tila Tequila.” Thus far, the approach hasn’t been any more selective, but the holes have disappeared—Boesch’s contact rate is only .8% below league average, an impressive figure in light of the fact that his swing rate is 13% above average (only Vladimir Guerrero, Jeff Francoeur, and Delmon Young have swung more often).
We weren’t alone in discounting Boesch’s abilities—Baseball America 2010 rated him Detroit’s 25th-best prospect, noting that he “struggles against left-handers and may not be more than a platoon player.” Thus far, that potential platoon player has posted a 1.386 OPS against same-sided pitchers. I don’t cite these seemingly errant outlooks in order to show the world how wrong it was about Boesch. Rather, I mention them to remind it that it most likely had the right idea to begin with, despite Boesch’s 3 months of blistering performance in 2010 (Boesch’s onslaught began with a.379/.455/.621 line in 66 April plate appearances at Toledo, which translated, both in theory and in practice, to a .333 TAv in the majors).
Boesch hit .273/.319/.434 in nearly 2000 minor-league plate appearances and was never young for his leagues. It’s true that he took a step forward offensively last season, leading the Eastern League with 28 homers, but BA belittled his power display as “inflated by Erie’s cozy ballpark,” and our translations didn’t paint a much prettier picture. Players who manage .658 OPSes against lefties in the minors don’t double that rate of production in the bigs, nor do they sustain .531 BABIPs, which Boesch has done against southpaws thus far. According to Chris Dutton’s simple xBABIP calculator, a player with Boesch’s major-league line would be expected to have a .283 BABIP overall. Boesch’s current BABIP is .374. As the Beatles sang, that's sure to fall, and as they sang later, it won't be long.
Boesch’s power display continued with a two-run bomb off of Cristhian Martinez yesterday afternoon (his second “lucky” homer of the season, according to Hit Tracker). Here are all the rookies in major-league history to finish with an Isolated Power of .275 or greater in a minimum of 200 plate appearances, with Boesch’s current mark included:
If Boesch really wants to finish the year on this list, he’ll find a way to suffer a season-ending injury in the near future. Half of the list is composed of current or potential Hall of Famers, a tenth is composed of Wally Berger (a good hitter in an abbreviated career, who looks even better after park adjustments), and for the remaining two-fifths (including Boesch, in all likelihood), well, it was all downhill from there. It’s probably appropriate that Boesch is currently tied with Kevin Maas, since Maas’ represents a much more likely career path for Boesch to follow than some of the list’s more revered representatives’. The career values of the players on this leaderboard are strongly correlated with the ages at which they cracked it, as well as the number of plate appearances in which they qualified to do so. The likes of Williams and Pujols sustained their appearances over full seasons despite barely having entered adulthood, while the Richards and Stuarts of the world snuck on via fractional seasons in their mid-20s. Boesch is quickly approaching the upper limit of how long mere mortals have managed to cling to their memberships in this august group.
If you can find someone willing to give you good odds against Boesch’s belonging to the following collection of 1.000+ OPS rookies at the end of this season, sell the house and plunk down your life savings:
It’s fair to say that the power is real (though likely not real enough to remain on the rookie ISO leaderboard—only 15 players finished last season with a HR/FB% as high as Boesch’s current 18.8%), but the average isn’t. One element of Boesch’s game hasn’t changed since his promotion—his unwillingness to take a walk. Boesch walked in 6.0% of his minor-league plate appearances, and in the midst of all the aforementioned swinging, has taken unintentional strolls in 6.5% of his plate appearances with the Tigers. That approach will play as long as he’s hitting .330, but when those hits start falling at a slower rate, Boesch’s power will have to be extraordinary for his bat to be an asset in left field.