Here’s a guest post from Andrew Kamholz, who contributes to the blog at Baseball-Reference.com:
Thanks to Andy for his contribution and please check out his stuff over on BR.
So far this year Victor Martinez is tearing apart lefthanded pitching to the tune of five home runs and 13 RBI in just 62 plate appearances. Aside from producing runs for the Red Sox, this will also help reduce the number of lefties that David Ortiz faces when he bats behind Martinez. Ortiz is much more dangerous against righties (one HR every 17.3 plate appearances in his career) than against lefties (one HR every 24.9 PAs).
In 2010 he’s getting on base more than half the time against lefties. That production, plus his assist to Ortiz, is the good news.
What’s the bad news? Check out how consistent Martinez’s numbers against lefties were before this year. In all of his full seasons (2004-2007 and 2009) his batting average against lefties was between .270 and .290. This year’s figure of .483 is an aberration. His slugging percentage is typically in the mid-to-high .400s, not .897 like this year. Before 2010 he homered once every 34.8 plate appearances against lefties, not once every 12.4 like this season.
It’s not terribly likely that at age 31, Martinez has learned better how to hit lefties. It’s far more likely that in this year’s relatively small sample to date, he’s had a few good bounces, smacked a few mistake pitches, or been helped by good hitters’ situations (such as having runners on base.) It is to be expected that for the balance of 2010, he’ll perform closer to his career averages than he has so far. Of course, with his hot start, 2010 will almost surley be his best career year against lefties.
While we’re at it, we can look at the opposite bad news/good news situation. So far in 2010, Martinez’s performance against righthanded pitchers has been the worst of his career with just a .209 batting average and pitiful .326 slugging percentage (compare to career averages against righties of .299 and .467.) That’s the bad news — the good news is that this performance will, too, move closer to his career averages. We can expect a lot more power from Martinez against righties the rest of the way.
To get a sense of just how good Martinez has been so far, check out his career splits against lefthanded pitching: