There will be firsts in this World Series, guaranteed.
Either the Tampa Bay Rays or Milwaukee Brewers will have the first ABS challenge of a ball or strike. One of them will have the first successful challenge. One of them will have the first lost challenge.
This is the first year that MLB brought the automated ball-strike challenge system to the highest level.
It had been sampled in Triple-A, but it arrived for the first time in this regular season. It has stuck around with the same rules for the playoffs.
For those tuning into baseball more heavily just for the World Series, we’ve got all the details for you on how this works.
Ironically, while we’re talking about it — the Rays and Brewers are two of the least common challenge teams in MLB this season.
But there’s still plenty to know.
What is ABS in Baseball?
ABS stands for automated ball strike, and it was the new challenge system brought MLB for the 2026 season.
It was previously tested out in the minor leagues, beginning in 2022, so many current MLB players already had experience with it before it showed up in the majors.
How many ABS challenges does a team get?
Each team starts the game with two challenges.
The challenge can be initiated by the batter, pitcher or catcher. It has to happen immediately after the home plate umpire’s call.
What happens in an ABS challenge?
The pitch that just happened is compared to an animated, predetermined graphic of the strike zone.
If the pitch touches any part of the zone, it’s a strike.
If a team’s challenge is successful, it retains the same number of challenges it had before the attempted challenge.
If it’s unsuccessful, that challenge is lost.
Essentially, you only get two incorrect challenges in a game — but before then, an infinite number of correct challenges.
How does a team do an ABS challenge?
The player that wants to challenge — the pitcher, catcher or hitter — taps his helmet or hat.
That signals to the umpire that a challenge has been made, and it’s supposed to happen within a second or two of the call. A home-plate umpire can deny the challenge if it seems to take too long, or if a player seemed to take directive from the dugout.
This season, the numbers worked how you might expect — catchers were the most successful at getting calls overturned. Hitters were next, and pitchers both rarely challenged and weren’t often right.
What’s Yandy Diaz Doing?
For those watching the World Series — Rays leadoff hitter Yandy Diaz didn’t challenge a single pitch all year.
Clearly, he’s just trying to focus on his own at bat.
World Series Ending Possibility
The craziest part of the ABS challenge system is that the World Series could end on a challenge.
Teams often change their challenges for the end of games, because that can often be the high-leverage setup.
It would be a bit odd to end a game that way, but they’re just trying to get the calls right.
How ABS Challenge System Works in World Series