This is something that we’ve always suspected intuitively, but Mike Fast has a major piece up over at Baseball Prospectus today exploring (a) how much of an influence a catcher has on ball/strike calls for borderline pitches; (b) the techniques they use to do this; and (c) who, among active catchers is the best at it. The upshot: the effect is way greater than you’d think for such a seemingly minor thing.
There’s pitch plot evidence to show who gets the calls and where and animated gifs showing the differences between the good catchers and the bad catchers in terms of how glove movement and head movement can impact whether a pitch is a ball or a stike. There is also, it should be noted, an unquantifiable piece to all of this which may depend on a catcher’s reputation, relationships with the umpires and that sort of thing. But there are clear trends in the data. And Jose Molina as a friggin’ boss.
Keith Law just read it and tweeted the same first observation I had: “The biggest impact of that … piece should be on umpires. It’s hard proof they are bad at calling borderline balls/strikes.” Yes, the human element, for lack of a better term, is going to be present when men call balls and strikes. But the borderline calls are bad and no catcher should have this much of an ability to impact the calls. Robots anyone? Or, short of that, maybe your team’s GM should give Jose Molina’s agent a call.
This is a major study that people who care about such things should bookmark.