What is the ABS Challenge System in MLB? How baseball’s new rule works

Major League Baseball has adopted technology designed to improve the accuracy of the game. One of the most talked-about innovations in recent seasons is the ABS Challenge System, which has been approved for MLB play beginning in the 2026 season.

For fans watching games, the system adds a new strategic element to baseball. Understanding how the ABS Challenge System works can help you follow the action more closely as MLB begins using the rule at the major league level.

What does ABS mean in baseball?

ABS stands for Automated Ball-Strike System, a technology that uses tracking cameras to determine whether a pitch crosses the strike zone.

The system relies on the same type of pitch-tracking technology used in broadcasts and advanced analytics. Cameras positioned around the stadium track the baseball’s trajectory and compare it to a digital strike zone set by league parameters and adjusted to each hitter’s height.

If a pitch passes through the defined strike zone, the system identifies it as a strike. If it misses the zone, it is considered a ball.

Some minor league experiments used ABS to call every pitch automatically. However, MLB’s current approach focuses on a challenge system, where the human umpire still makes the call unless a player requests a review. This hybrid model preserves the traditional role of umpires while adding a layer of technology to correct potential mistakes.

Why MLB has adopted ABS challenge system

The primary goal of the ABS system is to improve the accuracy of ball and strike calls. While home plate umpires are highly skilled, determining the exact location of a pitch traveling more than 90 miles per hour can be extremely difficult.

Technology offers a way to correct obvious mistakes while still preserving the traditional role of umpires in the game.

Another reason MLB prefers the challenge version of ABS rather than full automation is game flow. A fully automated strike zone could remove the human element entirely, which some fans and players believe would change the character of the sport.

By allowing limited challenges instead, MLB hopes to balance technological accuracy with the traditional rhythm of baseball. That balance was a major reason the league chose a challenge model instead of using ABS to call every pitch automatically.

How the ABS challenge system works

In the challenge version of ABS, players on the field can request a review of a ball or strike call immediately after the pitch is thrown.

The process is designed to be fast and simple so it does not significantly slow down the game. A player (usually the catcher, pitcher, or batter) signals for a challenge right after the umpire’s call.

Once a challenge is initiated, the automated system reviews the pitch location and determines whether the ball passed through the strike zone. The result is then displayed on the stadium scoreboard and broadcast graphics. MLB has said the review process takes about 15 seconds.

Each team receives a limited number of challenges per game. Teams begin with two challenges and keep them if the challenge is successful. If a game goes to extra innings, any team that starts an extra inning with no challenges remaining receives one challenge for that inning.

The goal is to allow players to correct obvious mistakes while preventing teams from challenging every close pitch.

Who can challenge a ball or strike call?

One unique aspect of the ABS Challenge System is that challenges must come directly from players involved in the pitch.

Only three players can initiate a challenge:

1. The batter

2. The catcher

3. The pitcher

Managers and coaches cannot request challenges from the dugout. This rule helps keep the game moving quickly because players must make the decision immediately after the pitch.

If a player believes the umpire made an incorrect call, they simply signal for a challenge without consulting the bench. The review then happens within seconds.

This player-driven approach is designed to keep the system simple while adding a new layer of strategy to the game.

Where the ABS system has been tested in baseball?

Before its adoption in MLB for 2026, the ABS system was tested in several leagues and events. One of the primary testing grounds was the minor leagues, where MLB often experiments with potential rule changes.

The system also appeared during spring training games in 2025 as the league evaluated how it affected the pace and flow of play.

Spring training games held at facilities like Salt River Fields at Talking Stick and Camelback Ranch included ABS challenge trials so players and umpires could become familiar with the process.

These testing periods allowed MLB to gather feedback from players, umpires and fans before deciding whether to implement the system during regular season games. That process led to MLB approving the ABS Challenge System for major league use starting in 2026.

See MLB’s new strike zone technology from the right seats with SeatGeek

Part of the fun of MLB using the ABS Challenge System is seeing how the process plays out inside the stadium. When a challenge happens, the pitch location is typically displayed on the ballpark’s video board, showing fans exactly where the ball crossed the plate.

Because these graphics appear on the stadium screens, where you sit can influence how easily you can follow the review. Seats with a clear view of both the field and the scoreboard make it easier to track challenges and see how the automated system evaluates each pitch.

As the official ticket marketplace of MLB, SeatGeek makes it easy to find those vantage points. You can explore interactive stadium maps, compare sections, and quickly see how ticket prices vary throughout the ballpark before you buy.

SeatGeek also highlights listings that stand out for value with Deal Score, helping fans zero in on great options—whether you’re looking for lower-level seats near the action (and the scoreboard) or a more affordable view from higher sections that still keeps the strike-zone graphic in sight.

By exploring different sections in advance with SeatGeek, fans can choose seats that provide a great vantage point for both the game itself and the new technology shaping baseball’s future.