Robot Umpires Coming to a Ballpark Near You

Now that the Super Bowl is in the rearview mirror, it seems appropriate to turn our technological attention to baseball.

So, batter up! Like it or not, America’s pastime is changing. And considering baseball fans’ feelings about tradition in the game, there’s going to be at least as much “not liking” as “liking” regarding this next piece of news.

Robot umpires are coming to a ballpark near you. The relatively newly developed electronic strike zone system will be used in all 30 Triple-A parks in 2023, seemingly another significant step toward the implementation of the technology at the big-league level soon. The change includes Victory Field, home of the Indianapolis Indians. They open there March 31.

Regardless of your feelings about automated ball and strike calls in baseball, the technological features of this emerging system are quite fascinating. While the system is robotic, there won’t be any actual robots behind home plate or anywhere on the field. But the ump behind home plate will be relayed information from a high-tech eye-in-the-sky system.

First things first, though. There will be two systems used in Triple-A minor league baseball in the upcoming season. The technology in both systems is essentially the same. It’s the way it will be deployed that is different. One of the systems will use computers and high-tech cameras to call all balls and strikes. The other system will have the human umpire make the calls and allow team officials to make a pre-determined number of challenges to those calls during the game.

It’s not yet clear which of those systems will be used in Indianapolis. Indians officials referred all questions to Major League Baseball (MLB) officials.

“As the season approaches, MLB will issue a press release outlining all of the rule changes for the 2023 season and once that happens, we’ll likely make a few members of our baseball operations staff available for questions,” says MLB spokesman Jeff Lantz.

But there are some details we do know.

Half of the Triple-A games will be played – using the automatic balls and strikes (ABS) system – with all calls determined by an electronic strike zone, and the other half will be played with an ABS challenge system similar to that used in professional tennis.

In the challenge system, each team will be allowed three challenges per game, with teams retaining challenges in cases when they are proved correct. The challenge system would certainly add another level of intrigue to the game, with batters and catchers likely needing some training on when to challenge calls.

MLB’s intention is to use the data and feedback from both systems, over the full slate of games, to guide future decisions on implementation of the system.

MLB has no firm date to implement its ABS system in the big leagues. But over the last four seasons, the robotic umpire has been used increasingly in the minor leagues.

Early in 2019, MLB officials announced a partnership with the Atlantic League of Professional Baseball (ALPB) to test new playing rules to observe the effects of potential future rule changes and equipment. One of those initiatives was the creation and testing of the ABS. The goal of the tests was to validate whether ABS was able to make and consistently communicate the correct call to the umpire quickly enough for the umpire to make the call on the field without introducing a delay. So while the call is determined robotically, it’s announced by a human (for the sake of argument we’ll continue to call him umpire).

Multiple Hawk-Eye (branded) cameras placed high up in the stadium are positioned to judge if a pitch is a ball or a strike. Though it’s not clear how many cameras will be used, it would be at least four, and likely more. The ABS strike zone is a 19-inch wide two-dimensional rectangle set at the middle of the plate. It’s adjusted for player size, so it can accurately call balls and strikes for 6-foot-7 Aaron Judge or 5-foot-6 Jose Altuve.

A human ABS operator is positioned high above home plate, in most ballparks it would be in the area of the press box. The human ump behind home plate receives the call in his earpiece and makes the call on the field. MLB officials are confident they have a system worked out where home plate umps will call balls and strikes using ABS just as fast as if they were making the calls themselves.

The primary inputs for ABS are the pitch arc – the path the ball takes as it proceeds from the pitcher to the catcher – and the location and dimensions of the strike zone. The pitch data generated by the MLB tracking system is composed of a set of polynomials describing the path the center of the ball travels through space in MLB’s standard coordinate system, where the y-axis points toward the pitcher’s mound from the back of home plate, the z-axis points directly up from the back of home plate, and the x-axis is orthogonal (bisects at a right angle) to the other two axes.

As soon as the pitch data has been generated by the tracking system, ABS uses that information and the current strike zone definition to determine whether the pitch is a strike. Math and science geeks can click here to read more about the math, science and tech particulars of the system. You can also read more about the Hawk-Eye branded system being used by professional baseball teams and the part tennis and television broadcasts played in the development of baseball’s ABS system in this MLB blog post.

MLB officials are calling the ABS system a game-changer. And that’s no joke – for better or worse. There’s a lot to discuss here, but one of the biggest objections for the baseball purist is how it will change the role of the catcher.

If MLB uses electronic strike zone calls for all pitches, it would dramatically change the function of the catcher, which for generations has been filled by players who have mastered defensive nuances – receiving the ball effectively, pitch presentation and debate with and influence over umpires – that would become all but obsolete with the ABS system. With a full ABS, catchers would be little more than human backstops that occasionally get to attempt to throw out stealing base runners or be involved in plays at the plate. Additionally, the umpires would have one of their primary responsibilities stripped away if MLB shifted to an electronic strike zone.

There’s also concern that if a robot can call balls and strikes, it could also officiate many other aspects of the game, potentially removing the human umpire even more – or perhaps someday altogether.

For that reason, many MLB and minor league officials favor the challenge system. Though no one (that I know of) has taken a poll, I’m going to guess that many baseball fans would also vote that way. The challenge system could create its own problems, chief among them would be slowing down the game.

MLB officials have worked hard over the last decade to try to speed the game along to keep fans’ attention in an increasingly gotta-have-it-now society.

There is already significant change in the season ahead, with the implementation of a pitch clock, new regulations greatly limiting the use of defensive shifts, larger bases, and a restriction on the number of times a pitcher can attempt pickoff throws. The alterations are intended to augment what MLB commissioner Rob Manfred has referred to as the “pace of action.”

With that said, let’s “Play Ball!” I’m pretty sure a human is going to continue to call that out at the beginning of each game.

Anthony Schoettle is the director of communications for the Indiana Chamber. He started with the Chamber in 2021 after a long career in journalism. He’s won multiple awards for his storytelling ability on a wide range of business topics.