Robot Umps and Velocity Incentives

Had a few calls gone differently in the ninth inning Sunday night, everyone could have gone to bed earlier. The poor beat scribes could have returned home, or to their Marriott Courtyards or SpringHill Suites, at a reasonable hour. I wouldn’t have fallen asleep on my couch. And the Cubs would have scored victory of sorts as they would have arrived to their charter flight earlier. The Cubs traveled to Denver after the game. The first night in adjusting to altitude in Denver after an 18-inning affair in Chicago is the kind of game some believe you can pencil in for a loss.

If Austin Romine could have had a better night receiving in the ninth inning, everyone could have enjoyed an earlier night. Romine is a league-average framer. Of course, it’s not easy to catch Aroldis Chapman.

Others have studied velocity and the affects it has on framing, including FanGraphs’ Jeff Sullivan way, way back in in 2013 when framing was still a relatively new development. Sullivan devised his own home-made recipe to quantify the effect:

For starters, the correlation between average fastball velocity and Diff/1000 is -0.26. For relievers, the correlation between average fastball velocity and Diff/1000 is -0.34. These aren’t real strong, but they are meaningful, and they don’t account for catcher identity. What the numbers show is that, the harder a guy throws, the less favorable a strike zone he gets.

For the first time, this season, we, the people, have the ability to search a more detailed strike zone at Instead of 13 zone to study, there are 29. I was curious to look at that new gray area on the edge of the zone you can search at Savant, zones No. 11-19 on the detailed search. I wanted to study borderline calls there by velocity. What I found:

Fastballs 92 mph or less: 2,805 called strikes, 2,602 balls (51.8% called strikes)
Fastballs between 93-96 mph: 2,474 called strikes, 2,627 balls (48.5% called strikes)
Fastballs 97 mph or greater: 251 called strikes, 363 balls (40.8% called strikes)

So a league average fastball, this season, has been called a strike 11% more often than a high-velocity fastball on the edge of the zone. That’s interesting.

Chapman threw eight fastballs in the border region Sunday night, five were called for balls. While many hitters probably feel Chapman has plenty advantages as is he could benefit from another one: a robot ump.

The balls:

The strikes:

This is not one of the pitches studied, but consider the amount of momentum created by this pitch to have Romine nearly skid into the home team’s on-deck circle.

This is also not one of the pitches in question, but it is glaring evidence to demonstrate it is not easy to simply to catch a 100 mph fastball if it is off target.

Catching Chapman ain’t easy.

The bottom of the ninth inning began Sunday night, with Chapman walking Addison Russell without controversy. Chapman missed badly with location.

Jon Jay followed by singling on a 2-2 pitch, but consider the 1-2 offering:

The 1-2 pitch was a ball, just missing the corner. But consider the movement of Romine, moving not just his glove but his upper body moving to his left, perhaps needing to get his body behind the ball to limit his glove being demonstratively moved out of the zone.

After a Wilson Contreras strikeout, Chapman began Albert Almora with this pitch, which was unjustly deemed a ball. We know the difference between a 2-1 and 1-2 count is nearly 200 points in batting average. So that missed call represents a significant swing in probability. Again, the 99 mph pitch caused some recoil to Romine’s glove.

Almora singled in Russell to cut the Yankees’ lead to 4-2. Javier Baez followed with a single to score Jay and make it a 4-3 score with one out. Chapman struck out Kyle Schwarber for the second out and then faced the reigning NL MVP with. The one-strike, one-ball offering to Bryant:

If Chapman gets that pitch perhaps he more aggressive attacks Bryant, gets the third out, and the Yankees win. Instead, Bryant is ultimately intentionally walked to load the bases and Chapman hits Rizzo to tie the score at 4. Nine innings later, the game ended.

Chapman did not get many benefits of the doubt in the ninth inning, rare velocity doesn’t help a pitcher in every regard. Sure, you’d rather have elite velocity than not have it. But sometimes it can hurt an arm.

Sunday was a glaring reminder that velocity must be taken into account when evaluating a catcher’s framing, along with playing on the road and trying to close out a game in the ninth inning in a hostile environment. Umpire ball-strike bias explains much of home-field advantage. Sunday night was also a reminder that as great as Chapman’s stuff is, sometimes it can work against him.

It is Chapman, and the other high-velocity arms in the game, that would benefit most from an automated zone. An automated zone, would make some of the most dominant arms even better.

A Cleveland native, FanGraphs writer Travis Sawchik is the author of the New York Times bestselling book, Big Data Baseball. He also contributes to The Athletic Cleveland, and has written for the Pittsburgh Tribune-Review, among other outlets. Follow him on Twitter @Travis_Sawchik.

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5 years ago

This is very interesting. Any time a significant change is made, it carries effects that are not immediately obvious.

Lucky for us, you’re here to delve into these effects!