Comparing the Best and Worst Pitcher Zones

Shortly before Thanksgiving, I wrote an article about how Chris Sale had been hurt last season by lousy receivers. That was an interesting observation from the data, but it wasn’t the only interesting observation from the data. According to Baseball Prospectus, Sale lost the second-most runs from his pitch-framers. Brandon Finnegan, however, pitched to the worst strike zone, his framers costing him an estimated 7.8 runs. Meanwhile, from the same source, Madison Bumgarner pitched to the best strike zone, his framers helping him by an estimated 11.0 runs. That’s a 19-run difference from catchers alone.

Maybe you don’t believe the spread was really that big. It’s easy to believe there was some spread — Bumgarner pitched almost exclusively to Buster Posey, while Finnegan pitched to Tucker Barnhart and Ramon Cabrera. One should also be wary of putting everything on the catchers. Pitchers with better command are easier to receive than pitchers with worse command, and Bumgarner throws with greater accuracy than Finnegan does. So, in part, the zones were the pitchers’ fault. But one thing we know for sure is that, in the end, Bumgarner’s strike zone was more generous. Arguably the most generous. So here is how the Bumgarner and Finnegan called strike zones compare:

Pretty interesting! Here is an alternate view of the same information. Note this is also from the catcher’s perspective. This shows called-strike rates out of all called pitches:

Both pitchers are southpaws. Bumgarner got the far better zone high. He got the far better zone arm-side. He got the far better zone low. Glove-side, it’s about equal, if not in favor of Finnegan. That’s of some note — Finnegan wasn’t losing strikes everywhere. It seems like he frequently tried to target that glove-side edge, but he’d often miss, and his catchers were probably worse at receiving missed locations. So it goes. It’s another example of a point to be debated. Bumgarner got the way more generous strike zone than Finnegan did. Some of this is because Bumgarner hit his spots better than Finnegan did. That reflects well on Bumgarner’s talent! But with an automated strike zone, the gap in performance between the pitchers would’ve been narrowed. Bumgarner’s zone would’ve been worse, and Finnegan’s zone would’ve been better. You either like the way things are, or you don’t. They’ve been this way forever, even if we’ve only recently taken to measuring it.

An estimated gap of 18.8 runs. This compares the two extremes, but there was about the same difference in WAR last year between Max Scherzer and Carlos Martinez. Individual ball and strike calls seldom make a big difference in the moment, but, holy hell, can the differences ever add up.

Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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