Batter/Pitcher Splits Crib Sheet

I don’t know about everyone else, but it can be somewhat difficult for me to keep track of all the different splits that are worth remembering. We all know that batters typically fair better against opposite-handed pitchers, but sabermetric knowledge has now progressed to the point where that’s not the only thing to keep track of anymore. What about batted ball splits? Does this pitcher throw a dominant changeup, and if so, what are the platoon splits for changeups?  How large of a sample size do I need before I can make assumptions about a player’s platoon split? It can be a lot of knowledge to remember, but it’s all important information in case you want to analyze a managerial move or lineup.

So below the jump, you’ll find a crib sheet for understanding lefty-right, batted ball, and pitch platoon splits. If you have any questions, feel free to ask in the comments.

Lefty-Righty Splits

    •Obviously, we all know that batters typically do worse when facing a same-handed pitcher (e.g. a lefty batter facing a lefty pitcher). However, we can’t make any overarching statements about how much batters struggle against same-handed pitcher; the size of a lefty/righty platoon split varies from batter to batter.
    •The same can be said for pitchers: while pitchers are normally better against same-handed batters, the size of a pitcher’s platoon split varies from pitcher to pitcher.
    •Batters don’t have their platoon splits stabilize until at least 1,000 plate appearances against each hand (around 2,000 for right-handed batters), while pitchers have their platoon splits stabilize much faster (500-700 plate appearances against both hands).

Batted Ball Splits

    •If a pitcher has an extreme batted ball profile – as in, they allow a high percentage of flyballs or groundballs – they will be more effective against batters that have a similar batted ball profile. In other words, if you put Tim Hudson (career 59% groundball rate) into a game against Johnny Gomes (career 51% flyball rate), I wouldn’t expect it to go well. Hudson would be more likely to succeed against someone like Derek Jeter, who has a career 57% groundball rate.
    •Batted ball splits can have just as large an impact on a matchup as lefty-righty splits, but they don’t come into play as often because most hitters and pitchers have a neutral batted ball profile.
    •Certain batted ball types are more likely to fall for hits than others. In 2010, line drives fell for hits 72% of the time, groundballs fell for hits 23% of the time, and flyballs went for hits 14% of the time. However, those percentages are based off BABIP, which excludes homeruns from its calculation; if you include homeruns, the flyball percentage bounces up to 21% of the time.

Pitch Splits

    •There has been lots of work done over the last couple years to determine if certain pitches are more effective against same-hand or opposite-hand batters. The general rule of thumb is that pitches that move horizontally (e.g. sliders) work best against same-handed hitters, while pitches that move vertically (e.g. curves, changeups) are most effective against opposite-handed hitters.
    •For a more complete list, here’s what I’ve been able to find over at Baseball Analysts and The Hardball Times:

Four-seam fastballs: Small platoon
Two-seam fastballs: Large platoon
Cutter: None
Sinkers: Medium platoon
Sliders: Large platoon
Changeups: Small reverse-platoon
Curveballs: Small reverse-platoon

    •In other words, pitchers should try and attack same-handed hitters with stuff like sliders, sinkers, and two-seam fastballs, while they should use changeups, curveballs, and cutters against opposite-handed batters. These are sweeping generalizations, though, and the optimal breakdown may vary depending on a pitcher’s movement and pitch repertoire.

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Steve is the editor-in-chief of DRaysBay and the keeper of the FanGraphs Library. You can follow him on Twitter at @steveslow.

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Craig Tyle
Craig Tyle

I’d be interested in a deeper dive into the components of lefty-righty splits. For example, I would think that differentials in a batter’s K% vs. LHPs and RHPs would stabilize quicker than differentials in BABIP.