Fun With Brennan Boesch’s Un-Fun Platoon Splits


Can Brennan Boesch hit enough to stick with the Tigers in 2013? Mandatory Credit: Kim Klement-USA TODAY Sports

Brennan Boesch hits lefties better than righties” is a line we’ve heard repeated since his rookie season that saw him hit for an OPS of .951 against left-handed pitchers and only .673 versus right-handers. The phrase has been less-often repeated the last couple of years, but still his career batting line favors his time against same-handed pitching (a .767 OPS vs. a .717 OPS).

It’s possible that some players really do have a propensity toward this type of reverse-platoon split, but it would be incredibly rare for a hitter, and it’s something we should never expect. Especially for a guy with less than three full seasons under his belt. So there’s two ways we could look at this. (1) That his OPS versus righties has been suppressed due to random variation and should therefore increase, or (2) that his OPS versus lefties has been the result of good some favorable luck and should drop in the future. Unfortunately for Boesch (and the Detroit Tigers) #2 is probably what we’ll see from him going forward.

The issue here is that, while he’s had over 1,000 plate appearances versus right-handed pitchers, he’s had fewer than 400 versus left-handers. 374 appearances (to be exact) seems like a big number, but it’s really not that large in a statistical sense. We know that small samples in baseball include a large amount of random variation which causes the numbers we observe to not be “real”. It’s true that Boesch has hit for a .767 OPS versus lefties, but that’s probably not his “true talent” versus lefties.

And when it comes to random variation in small samples in baseball, we’re often going to talk about batting average on balls in play. Versus right-handed pitching, Boesch has posted a .278 BABIP. Versus lefties that number jumps to .364. Hitters do have much more control of their BABIP than pitchers do, and it’s entirely possible that hitters could have different true talent BABIP levels versus each pitcher handedness, but it’s unlikely that the 86-point difference we’re seeing is real. It’s very likely that his BABIP talent is (against both righties and lefties) is much closer to his .298 overall career average (which is pretty much dead on league average).

If we were to assume that his strikeout, walk, and home run rates were “real”, and simply adjusted his splits to his career average BABIP of .298, we’d see a different looking hitter. His overall line wouldn’t change, but we would come up with expected splits of .748 OPS versus righties and .652 OPS versus lefties. This would actually make him look like a more useful platoon player (than his current career splits suggest), but those aren’t encouraging numbers as we look toward his future.

A .748 OPS is not a good number for a corner outfielder who’s supposedly the strong side of a platoon, and if he didn’t platoon his overall line would be downright horrible for the position. The expected OPS split of .748 is very nearly league average for the position (which isn’t altogether terrible), but with Boesch you’d be getting that with well below average defense. We’re definitely still talking an above replacement level player, but not really any more than a 1 WAR guy.

The Tigers have agreed to pay him $2.4 million for the upcoming season. That’s not an unreasonable total right now, but he’s going to have to show vast improvement as a hitter (or defender, or both) in order for the Tigers to justify investing even more money in him for in his second and third arbitration years.

I don’t know what the Tigers’ plan for Boesch is this season, but they’ve committed to him for now, and probably owe him (and themselves) a somewhat extended look to determine what they want to do in the coming years, but there’s no one you would want to boot from the lineup to make that happen.