I’d planned on writing an analysis of the Tigers bullpen for this year. However, a discussion on Primer inspired this post instead. Craig Monroe was a stud against lefties last year, and a dud against righties. Can we expect the same this year?
I frequently read the Clutch Hits at Baseball Primer because they not only provide a number of links to interesting articles, but because the discussions that ensue are quite interesting. This particular thread deals with the expected platoon splits of right handed batters. Essentially, data shows that for all right handed batters the ratio of their OPS versus left handed pitchers to their OPS versus right handed pitchers is 1.09. In other words, right handed batters hit southpaws nine percent better than right handers. This makes sense and is to be expected.
Now here’s the interesting part. This is the expected ratio for all right handed batters. That is, given enough plate appearances right-handed batters will approach this average. Furthermore, there aren’t really hitters who are more adept at hitting left handers over right handers than their peers. So while some hitters hit left handed pitchers very well, those are also commonly the hitters who hit right handers better than their peers also.
If this all seems confusing, don’t worry, it is. Dodger Thoughts has done a much nicer summary than I have. But my point in bringing this up isn’t to necessarily explain it all. More I wanted to look at Craig Monroe.
Monroe’s OPS in 268AB’s against righties was .600, and against soutpaws it was .900 in 157AB’s. The resulting ratio is 1.61, or tremendously higher than the expected 1.09. If we are to believe that all right hand hitters will move towards 1.09 that means that in the coming years Monroe will either improve his performance against righties, or not perform as well against lefties (or both).
The point is that I was convinced that Monroe definitely should be starting against lefties next year over Sanchez/Higginson. While I still think he should, I just shouldn’t expect him to achieve an OPS of .968 when he does.
The larger question that will only be answered in time is whether or not Craig Monroe is closer to the .600 OPS guy, or the .968 OPS guy.