Explaining spring training's ABS system after Max Muncy’s first at-bat for Dodgers

The Dodgers opened spring training on Thursday afternoon with a matchup against the Cubs, and something weird happened in the bottom of the first. With Chicago's Cody Poteet pitching to Max Muncy in his first at-bat of the year, Poteet got himself to an 0-1 count before throwing his second pitch, a fastball at the bottom of the zone.

Home plate umpire Tony Randazzo called it a ball, but Poteet reached up and patted the top of his head as he returned to the mound. Randazzo copied the movement to confirm he'd seen it, and then the game went into a short delay.

That was the signal to call on the ABS — the automatic ball-strike challenge system. The pitch went under review, just like a manager might call for a review on an iffy play at any of the bases. The ABS confirmed that Randazzo was wrong, and the ball caught the right side of the zone to fall in for a strike and an 0-2 count on Muncy.

So what is the ABS, why are teams using it in spring training, and what does it mean for the game going forward?

Max Muncy's first spring training at-bat gave Dodgers fans their first look at the ABS system

The ABS has been used in the minor leagues since 2019, so Poteet was no stranger to it, but MLB will be using it in five different ballparks in Arizona and even more in Florida to try to forge its path forward at the major league level.

It works pretty simply: only the pitcher, hitter, and catcher are allowed to ask for a review on a certain pitch, and prompting from coaches or other players is prohibited. Both teams get two challenges per game, and they work the same way as the ones we're used to; if a challenge is upheld, the team that called for it loses their challenge.

This is an attempt to bridge the age-old gap between players and umpires, whose zones typically end up looking more oval-shaped than rectangular, the shape the ABS references. It's not a full movement toward a completely automated umpiring system — the umpires' union would never stand for that — but it is a way to give players some power back, especially in high-leverage situations.

The Dodgers had even joked before the game that Muncy was the only player not allowed to challenge, with Dave Roberts saying, "He’s our biggest culprit of not agreeing with the strike zone, so I said, 'Save your challenges.'" Still, he ended up being on the receiving end and victim of one anyway.

MLB is testing the ABS in so many different ballparks this spring that they should probably get a decent sample size of responses to it by Opening Day. There are no guarantees it'll end up in the majors, but we could be witnessing the beginning of a new era.