What Is MLB's ABS Challenge System? How Baseball's Newest Mechanism Works

For the first time ever the Automated Ball-Strike (ABS) Challenge System will be used in the World Series — when a pitch is challenged a strike‑zone graphic will pop up on the screen (the system debuted in MLB this season and was used in the minors and the 2025 All‑Star Game).
To challenge, a player must immediately tap their helmet/cap — only the batter, pitcher or catcher can request it — and each team gets two ABS challenges per game (they keep them if overturned and get an extra challenge per inning in extra innings).
The system already changed a playoff outcome (a 10th‑inning call was overturned to end a Wild Card Game), and the Rays vs. Brewers World Series, both chasing their first title, starts Oct. 23 on FOX.