What You Need To Know About MLB ABS System

 MLB's Joint Competition Committee voted 9-2 to approve the Automated Ball-Strike (ABS) Challenge System for the entire 2026 season. This includes spring training, regular season, and the postseason. It will be powered by T-Mobile's 5G network and Hawk-Eye technology. This hybrid approach keeps human umpires in the hot seat but arms players with a high-tech safety net for those game-altering missed calls.

Let's break down how this will work during an actual game. 

Human Ump First: The home-plate umpire calls balls and strikes as usual, relying on their eyes and experience.

Challenge Trigger: Only the pitcher, catcher, or batter can initiate a review by immediately tapping their helmet or cap—no dugout signals or manager histrionics allowed. Teams start with two challenges per game, and you keep 'em if you're right.

Tech in Action: Hawk-Eye's 12 high-speed cameras—tracking the ball with a margin of error of just one-sixth of an inch—kick in. The system plots the pitch's path against a batter-specific strike zone: a two-dimensional rectangle spanning the plate's full 17-inch width, with the top at 53.5% of the player's height and the bottom at 27%. (Player heights will be certified via biomechanical scans in spring training.)

The Verdict: The call flashes on stadium videoboards almost instantly. If ABS overrules the ump, the pitch is adjusted—no time wasted on booth reviews. Extra innings? If you've burned both challenges, you get one fresh per frame.

Limits and Logistics: Challenges spike in high-leverage spots—full counts saw 8.2% usage in spring tests—but they're rare on early-count tosses (just 1.6% on 0-0). No reviews on intentional walks or hit-by-pitches, and the system's decision is final.

The MLB had the ABS system in full effect during the 2025 spring training. The challenges had a 52% success rate. It took an average of 13.8 seconds to get a verdict. 

MLB's ABS rollout caps a modernization sprint that's shrunk nine-inning games by 30 minutes since 2023. It won't eliminate every beef shadow-zone calls in low-leverage spots stay ump-called, but it could slash late-game controversies that swing pennants. With the umpires' union already on board via last offseason's CBA, implementation hurdles look minimal.