MLB’s ABS challenge system has Diamondbacks fans debating pros and cons

First implemented in the minor leagues, the system made its way to Spring Training and the All-Star Game in 2025, where it was tested at the major league level. 2026 marks the first year of its permanent use in MLB.

The system works to correct any pitches that the pitcher, batter, or catcher believes were called incorrectly. With all players measured before the start of the season, the system detects where their strike zone is and determines whether pitches are called correctly.

So far this week, the ABS has been a dramatic part of games, as strikeouts are overturned and at-bats continue, or balls just slightly grazing the strike zone are called strikes.

For the Diamondbacks, they’ve seen two of these instances both for and against them.

Mar 26, 2026; Los Angeles, California, USA; Arizona Diamondbacks outfielder Corbin Carroll (7) hits a single to right field against Los Angeles Dodgers starting pitcher Yoshinobu Yamamoto (not pictured) during the fourth inning at Dodger Stadium. Mandatory Credit: Kirby Lee-Imagn Images

On Opening Day against the Los Angeles Dodgers, D-Backs’ Corbin Carroll challenged a high pitch initially ruled a strike, but it was overturned after the system showed the ball was two-tenths of an inch off the zone.

Then, on Tuesday, Detroit Tigers’ Kerry Carpenter challenged a close pitch below the zone that was called a strike and was able to overturn it after the system showed it was less than one tenth of an inch off the zone. He would eventually walk in that at-bat.

Fans online have mixed reactions to these calls, with some saying the system wasn’t made for these types of decisions and that some of these pitches are meant to be borderline, as pitchers typically look to paint around those lines.

In my opinion anything 0.1” shouldn’t be overturned…

— David S (@dms91) April 1, 2026

Bookmark this – AI will still swing moments in a game when it can https://t.co/N0tCjV07Jz

— Lfunbags (@Lfunbags) April 1, 2026

Others argue that a line needs to be drawn between strikes and balls, where precision is more important.

Looks like ABS got the call correct

— Scott Allen (@azsportsguy) April 1, 2026

This is how ABS should be used and every call should be from ABS.

— 🌵 Mr. Az (@MrAzSports) April 1, 2026

The ABS is just one of many initiatives to give teams more agency over how the game is called, with questionable calls influencing game outcomes throughout the sport’s history. Now, even if it’s less than a tenth of an inch, players can be sure the right call is made.

It also adds another layer to the game’s psychology. With only two challenges per game, knowing when to use them will be just as important as any other aspect of the game. Waste challenges early, and teams won’t have any recourse for potential, obvious missed calls.

Mar 31, 2026; Phoenix, Arizona, USA; Detroit Tigers right fielder Kerry Carpenter (30) hits an RBI single against the Arizona Diamondbacks in the second inning at Chase Field. Mandatory Credit: Rick Scuteri-Imagn Images

As Arizona and the rest of the league use this new system to their advantage, fans will continue to debate whether this change is ultimately for the better.