New Appeal Option Comes to MLB — What Is the ABS Challenge System?

In 2026, Major League Baseball (MLB) rolled out a new system that would allow players a more efficient way to challenge strikes. It's a controversial system, sponsored by T-Mobile, and it has already been implemented.

The Automated Ball-Strike (ABS) Challenge System has sparked a conversation about the use of umpires in baseball and whether or not it makes sense to incorporate more robotic aids in the game.

Here's what we know about what the ABS Challenge is.

The Automated Ball-Strike Challenge System uses a series of cameras and robot (AI)-assisted programming to review challenged balls or strikes to determine whether or not a call from an umpire is accurate.

On their site, MLB touted the program as "a technological advancement that will not only help ensure the most important calls are made correctly but also add a fun new layer of strategy to the sport."

They added, "This system of replay recourse has been fully reviewed and is seen as a happy middle ground between so-called 'robot umps' that could call every ball and strike and the long-standing tradition of human umps and the nuance that can come with their calls."

Each team starts the game with the option to challenge twice per team. The program "monitors the exact location of each pitch, relative to the specific batter’s zone."

Once a challenge is made, a replay of the pitch in question will be run through the program and then displayed on the video screen to determine the call.

Unsurprisingly, the advent of the ABS Challenge System has stirred some controversy among players and fans. While players seem to be singing the praises of the system, perhaps prompted by the league, fans are a little more skeptical.

But they got to see it in action in March 2026 when Jose Cabellero became the first player to issue a challenge and use ABS to review a strike.

Jose was handed a strike, but it was questionably close, prompting him to request a review. The system proved that it was a strike, but just barely.

However, the fact that it was able to pick up on such a minute discrepancy means that it's doing something the human eye struggles with.

Some worry that this will make umpires obsolete.

On TikTok, one user wrote, "This is not better for the game. Catchers framing pitches is an art form and a skill that can add to their worth. It’s dumb." But another countered, "They should've used it more that game tbh. Ump was absolutely dreadful for both sides and they kept letting him get away with it."

One user celebrated the concept that it might eventually get rid of "useless umps," while another wrote, "I hope we get to the point where a robot calls every single ball and strike." Another agreed, explaining, "This should be the umpire for balls and strikes. Not 4 times a game. What batter or pitcher will get pissed off with a machine? What machine would be offended by a player's disbelief in a call? None."

However, another user mused that taking the human element from a game that is notably a celebration of human skill "loses the plot."

For now, ABS is being rolled out for limited use. But that could change over time.