The Giants have confirmed that top pitching prospect Madison Bumgarner will make his 1st start of the 2010 season tonight against the Boston Red Sox. Why am I so nervous? Well, mostly because Bumgarner is getting a pretty tough assignment in the Red Sox. This year the Sox have been pretty tough on lefties — against LHP they rank (#1) in wOBA, ISO, sOPS+, and OBP.
Some data, the top 10 teams in the majors against LHP ranked by wOBA.
| Rank | Team | OBP | OPS | sOPS+ | ISO | wOBA |
| 1 | BOS | 0.364 | 0.847 | 131 | .207 | 0.367 |
| 2 | DET | 0.360 | 0.819 | 124 | .177 | 0.363 |
| 3 | NYY | 0.363 | 0.814 | 123 | .176 | 0.363 |
| 4 | MIL | 0.349 | 0.811 | 121 | .194 | 0.360 |
| 5 | ARI | 0.352 | 0.799 | 118 | .190 | 0.359 |
| 6 | WSN | 0.363 | 0.798 | 119 | .161 | 0.357 |
| 7 | CIN | 0.348 | 0.777 | 113 | .157 | 0.354 |
| 8 | NYM | 0.348 | 0.774 | 112 | .141 | 0.352 |
| 9 | CHC | 0.345 | 0.793 | 117 | .167 | 0.350 |
| 10 | SFG | 0.348 | 0.759 | 108 | .140 | 0.345 |
sOPS+ is the split version of OPS+, meaning that the Red Sox hit LHP +31% better than your league average offense (when hitting against LHP).
To this point, Bumgarner has spent his entire year in AAA Fresno pitching for the Grizzlies. The results have been both good and bad. He’s still not striking out hitters like he was when he dominated the lower minor leagues — he owns a rather pedestrian 6.15 K/9 in AAA — and it’s likely that in the majors, he’s going to play as more of a 5-6 K/9 guy. Prospecthounds will remember that while pitching in Augusta in 2008, Bummarner posted a K/9 of 10.16. Those days seem long gone. He’s pitched 2 years in a row now with K/9′s closer to 6. The good news is that he’s still throwing strikes — 2.29 walks per 9 in AAA — and his velocity readings have generally been better. Most games he seems to work around 88-92. It’s not the mid-90′s that made him so sexy as a prospect, but often times minor league velocity readings are somewhat exaggerated (see: Williams, Jerome).
Bumgarner’s other development this season has been an uptick in his ground ball percentage. He’s added incrementally to his GB% as he’s gone up each level (A: 41.6%, A+/AA: 42.9%, AAA: 46.2%). He’s reportedly been working on a cutter this year in AAA, too. That could have an impact on his ability to coax more groundballs. Hopefully what we’ll see tonight in Bumgarner, as opposed to his brief time in the majors last year, is a pitcher that works around 90mph most of the time, has a good feel for his fastball, and (hopefully) has improved his slider. Bumgarner’s presence on the roster should also mean an end to the phrase: “Todd Wellemeyer, starting pitcher.” and that’s never a bad thing for a team with playoff aspirations.
Also, Buster is catching tonight. Hallelujah!
