Quick Scoop

ABS in MLB is the Automated Ball-Strike Challenge System: it is **not** full robot-umpire baseball. Instead, the pitch is tracked by technology, and only the **pitcher, catcher, or batter** can immediately challenge a ball/strike call, with each team getting **two challenges per game** and keeping them if the challenge is successful.

How it works

• The system uses pitch-tracking cameras to judge where the pitch crossed the strike zone.

• The strike zone is individualized to each hitter, based on measured height, with the top and bottom set using MLB’s ABS rules.

• If a player challenges right away, the call is reviewed and shown on the scoreboard and broadcast.

• If the challenge is upheld, the team keeps that challenge.

• The process is designed to be quick, taking roughly 15 seconds.

Big idea

The goal of ABS is to correct the most obvious missed ball/strike calls without removing umpires from the game entirely. MLB’s 2026 rollout uses the challenge format because players preferred that over fully automated calls on every pitch.

What fans notice

A challenge usually creates a short pause, then the pitch location graphic appears and the crowd sees whether the call stands or changes. The most common strategic tension is whether a team wants to “spend” one of its challenges early or save it for a big moment later.

If you want, I can also give you a super simple 3-line version or explain how the strike zone is measured for each hitter.