ALDS Preview: Indians-Red Sox Umpire Strike Zone Analysis

Umpire Strike Zone Analysis

While the players involved in every playoff series have the largest impact, there are six men on the field who have an impact whether we like it or not. The human element isn’t going away and we have a method to analyze it. Ian York went to his PITCHf/x charts and performed an umpire strike zone analysis for the Cleveland Indians and Boston Red Sox ALDS.

MLB has announced the umpiring crew for the 2016 Boston Red Sox/Cleveland Indians ALDS: Brian Knight, Phil Cuzzi, Tony Randazzo, Paul Emmel, Bill Miller (crew chief), and Vic Carapazza.

We have shown before that umpires are very good at calling balls and strikes, and that they have actually improved in their ball/strike discrimination since around 2010, when official video review of umpire strike calls was introduced. However, we have also shown that different umpires have slightly different strike zones, with some being more likely to call a relatively large zone and others typically calling a smaller strike zone. How does this group of umpires fall out?

In these charts, we compare the likelihood of a strike being called in each sub-region of the strike zone, for the individual umpire compared to all major-league umpires. Areas where our umpire of interest is more likely to call a strike are shaded red; areas where he is less likely to call a pitch a strike are blue. The intensity of the color reflects the amount of difference from the average. Almost all the differences are located around the edges of the strike zone (the grey polygon in each chart), since pitches well outside or comfortably inside the zone are going to be called the same by all umpires.

Two of these umpires call virtually neutral strike zones. Phil Cuzzi (who will call Game 2) and Tony Randazzo (Game 3) both call balls and strikes that almost perfectly match up with the average umpire’s zone:

Randazzo may have a small region (up and inside to right-handed batters) where he expands the zone a little, but otherwise he is essentially average.

Brian Knight (calling balls and strikes in Game 1) is also just about average. He does seem to shift the left-handed batter’s zone outside and up slightly, calling slightly fewer strikes on the inside bottom corner and slightly more on the outer and top edges, but the differences are slight, as seen by the muted colors here:

Vic Carapazza – who ran into ball/strike controversy when calling last year’s Blue Jays/Rangers series – will not be at home plate in this five-game series. Carapazza is pretty much average with right-handed batters, but does the reverse of Knight with lefties, moving the zone inward. The effect for Carapazza is quite a bit more significant than for Knight:

Paul Emmel and Bill Miller, who will call Games 4 and 5 (if necessary), are both more extreme. Emmel calls a fairly small strike zone, especially with left-handed batters, taking away called strikes on the inside, top, and bottom, without expanding the outer edge to compensate. His zone for right-handed batters is very close to average, or perhaps very slightly expanded:

Emmel did come out near the top when we analyzed umpires’ out-of-zone calls over several seasons, so although he calls a small zone, he does so consistently.

Miller, on the other hand, has consistently called one of the largest strike zones in the majors, as we showed last year, and he hasn’t changed his tendencies this season. His zone for right-handed batters is expanded all the way around, especially at the top, and to left-handed batters he is also much more likely to call a high strike:


In general, players seem to be comfortable with an umpire calling whatever zone they prefer, within reason (so long as they are consistent: a pitch that is a ball in the first inning should be a ball in the ninth), so these different zones are not likely to disconcert the professionals. If the series goes five games, they will need to adjust to the contrast between the small strike zone of Emmel, with the very large zone of Miller. Additionally, it is something that pitchers and catchers may try to take advantage of, since they certainly will be aware of these tendencies.  

Follow Ian on Twitter @iayork.

Featured image courtesy of John Sleezer/Kansas City Star.

About Ian York 208 Articles
Ian is an immunologist and virologist who lives in Atlanta with his wife and two sons. Most of his time is spent driving his kids to baseball and soccer games, during which he indoctrinates his children on the glories of Pedro Martinez, the many virtues of the Montreal Expos, and other important information.

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