MLB Catcher Splits
How pitchers perform by catcher
Catcher splits are noisy. Most pitcher-by-catcher gaps are small-sample variance, so projection adjustments are heavily shrunk and only applied when a pitcher has 5+ starts with the catcher and at least 2 catchers with enough starts.
No slate data available for today.
MLB pitcher performance by catcher
How each starting pitcher's results have looked depending on who was catching, including strikeout rate per nine innings and the resulting adjustment to a projection when a particular pairing is in the lineup.
How to read these splits without overreading them
Catcher splits are among the noisiest data in baseball. A pitcher may have thrown to his backup catcher six times across two seasons, and the difference in results across that sample tells you nothing you can bet on. Treat a large gap on a small sample as a curiosity rather than a signal.
There are also real reasons a split can exist that have nothing to do with the catcher. Backup catchers often start day games after night games, against different opponents, and sometimes specifically when a particular pitcher starts. All of those confound the comparison, and none of them are about the catcher's ability.
The honest position is that most of what looks like a catcher effect is sample noise plus scheduling. It is worth checking, mostly so you are not surprised, and it is not worth building a projection around unless the sample is large and the gap is consistent across multiple seasons.
Where a battery change actually matters
The clearest case is a pitcher who has thrown almost exclusively to one catcher and is suddenly paired with someone new. That is a genuine change in circumstance even if the average size of catcher effects is small.
The more reliable use of this page is simply knowing who is catching, since it tells you the lineup is not the standard one. A backup catcher usually means a weaker bat in the order, and that is a measurable effect on team run expectation regardless of anything happening behind the plate.
Frequently asked questions
Do catcher splits actually predict pitcher performance?
Weakly at best. Most observed gaps are small samples and scheduling differences rather than a repeatable effect.
How large a sample do I need?
Many starts across more than one season before a gap should change how you bet a pitcher.
Why do backup catchers show different numbers?
They start in different circumstances, often day games after night games and against different opponents, which confounds the comparison.
What is the most useful thing on this page?
Knowing which catcher is starting, since a backup catcher usually means a weaker spot in the batting order.
Is the catcher splits tool free?
Yes, every split with a free account.