Robot Umps Will be Calling Pitches at Future MLB Games

By: Patty Rasmussen  | 
TrackMan ABS system
TrackMan Automated Ball-Strike (ABS) systems could replace human home plate umpires in Major League Baseball games as soon as 2024. TrackMan

Forget angels in the outfield. What about robots behind home plate? Ever since the words "Play ball!" were first uttered, baseball fans have bellyached about the quality of the umpiring, especially when it comes to calling balls and strikes.

But from the be-careful-what-you-wish-for category comes the TrackMan Automated Ball-Strike (ABS) system. And Major League Baseball (MLB) is poised to expand the automated strike zone experiment from Low-A to Triple-A, the highest level of the minor leagues and just a mere call-up from big leagues.


How Robo-umpires Work

The ABS system – AKA "robo-umpires" – doesn't look anything like we hoped or imagined it would. (C-3PO in dark slacks, a black polo and a chest protector? No such luck.) The ABS system is essentially a flat black box situated high behind home plate. It looks almost like a flat screen television that's not turned on.

But it's super advanced and uses radar and synchronized cameras to track just about everything on a pitch, including its release speed and height, spin rate and axis, extension, and vertical and horizontal release angles. As far as the strike zone goes, it tracks the home plate height, plate side, and vertical and horizontal approach angles. Let's see a human umpire do all that.


After recording these stats on a pitch, the system determines whether it's a ball or strike then relays the information to the human umpire on the field via earpiece and smartphone. The human umpire makes the call, and can override the ABS system if he disagrees.

The Method to the Madness

After the world of "I Robot," the system's operation seems like a bit of a letdown. But there's a method to the methodical-ness.

Think about it: Calling balls and strikes should be the most precise aspect of any baseball game. And now, with a computer picking up the pitches within the designated parameters of the strike zone, it — presumably — will be more accurate than relying on a human who is easily distracted and fallible at home plate.


The process has its fans and its detractors.

The system tends to call more strikes — including higher and lower strikes — and often displays an acute sensitivity to checked swings. The software appears to have some trouble with breaking-ball pitches that drop in front of the catcher, but that's where the human umpire element still comes in.

And you know this had to happen: In 2019, Frank Viola, pitching coach of the High Point Rockers in the Atlantic Coast League, was the first person in baseball to be ejected for arguing the strike zone with a robo-umpire. (More precisely, Viola's anger was directed at human umpire Tim Detwiler for not overturning the ruling on the field.) The former Twins ace (and Cy Young winner) later tweeted that his biggest beef was not knowing who was in charge — TrackMan or the human umpire.

Regardless, Hall of Fame third baseman Mike Schmidt wrote a piece for the Associated Press in 2019 advocating the further testing and use of robotic umpires stating it would "change the game for the good" and "continue to eliminate human deficiency."

In announcing intentions to put the system in place for testing in Low-A Southeast, MLB said it believed TrackMan would ensure consistency in the strike zone and improve the pace of the game.

There's no word on when ABS might be seen in major league ballparks. The Major League Baseball Players Association (MLBPA) put the kibosh on robo-umps in major league parks in 2023 during the most recent labor negotiations, but MLB commissioner Rob Manfred told ESPN he would like to have them in ballparks by 2024.

MLB umpire
Home plate umpires like Jerry Layne, seen here at a New York Yankees vs. Cincinnati Reds game at Yankee Stadium July 14, 2022, could soon be working alongside radar-tracking "robots."
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