Major League Baseball has introduced a tennis-like system allowing players to challenge ball and strike calls for the 2026 season.
The New York Yankees will take the field at Oracle Park in San Francisco on March 25 to open the 2026 MLB season. Taking the field with them will be an army of robots.
For the first time in MLB history, umpires will not be the final arbiters of balls and strikes.
Now, the Automatic Ball-Strike (ABS) system will allow teams, through a simple tap on the helmet, to challenge an umpire’s call twice per game. Of course, baseball loves to overcomplicate, so “twice” comes with both caveats and strategic implications.
Here are the rules. First, if a team’s challenge is successful, they retain it, like the HawkEye system in tennis. Second, a team receives one challenge per inning in extra innings. Third, teams can no longer challenge pitches when a position player takes the mound in a blowout. And fourth, only pitchers, catchers and batters may challenge (with no help from the bench).
Not to be dramatic, but the robot umpires have the ability to fundamentally change the game of baseball as we know it, and not just because we are going to be blessed with the hilarious sight of Yankees outfielder Aaron Judge whacking himself in the head a few times a game.
A new system to determine balls and strikes must be programmed using a precise definition of a strike zone. It just so happens that the ABS-defined strike zone is significantly different from what batters, pitchers, umpires and fans are accustomed to.
Previously, a strike needed to cross home plate above a player’s knees and below his chest. That ambiguous standard brought heaps of variation. If a player crouched, his strike zone was smaller. If he was a 6-foot-7 gargantuan like Judge, umpires accustomed to a typical strike zone would call a strike at his ankles because, for most players, the pitch was at knee-height. Umpires could easily be tricked by random factors, such as the height a player wore his socks at.
The variation was fun — until a close call went against your team, and then it was history’s greatest tragedy.
Now, the ABS-standardized strike zone will be individualized and based on each player’s precise height. The top of the strike zone will be at 53.5% of his height and the bottom at 27%. There is a non-zero chance that MLB picked these numbers out of a hat.
But the most interesting part of the ABS system is not about its accuracy. Nor is it about fairness. It is the strategy element.
Teams only have two chances to challenge — who should be allowed to take them? And when?
On the defensive side, if I were a manager, I would only let my catchers challenge. While pitchers are technically permitted to challenge, they are 60 feet and 6 inches away from the ball when it crosses the plate. Catchers are about five inches away, giving them a much better vantage point.
Offensively, the game is a lot more complicated. To maximize the chance that the challenge is worthwhile, I would only let my players with the highest on-base percentage challenge. I would also limit players to challenging called third strikes, rather than first or second strikes. And I would — with all due respect to Yankees second baseman Jazz Chisholm Jr. — only allow players with a good eye for balls and strikes to call for a challenge.
Whether a player can call a challenge should also be context-dependent. First inning, no one on base? Don’t even think about it. Ninth inning, runners on first and second with two outs? I’d give players a lot more latitude. These two examples are extreme; however, it is the edge cases that will require more gamesmanship.
There are also implications on player development itself. Right now, catchers have three main roles — batting, throwing out runners and framing pitches. Framing, which is a fancy word for moving your glove around to trick the umpire, will not work on robots. Because of this, it is an open question whether the value of a defensive-minded catcher will sink.
And what about you, dear reader?
Well, you will no longer be able to see the handy-dandy strike zone box on a live broadcast anymore. That is a precautionary measure, so that no one — especially not certain trashcans belonging to the Houston Astr*s — has information in real time that can be used to help players decide when to challenge. But what you will lose in live viewing experience you will gain in statistical conversation fodder: Surely there will be statistics available about which umpires get overturned the most and how competent various hitters are at challenging pitches.
The new ABS system will change quite a bit about the game of baseball, but it will not leave us deprived of reasons to yell at the TV — and to us Yankees fans, that is what matters most.