The ABS Effect

Which teams and players have benefitted the most from the ABS system?

The automated ball-strike challenge system, after seven years in the minor leagues, debuted in the MLB regular season in 2026. In nearly one full month, catchers and hitters have tapped their helmets 1,663 times already, with 54% of calls being overturned.

In just the 30 or so games teams have played as of April 25, it’s hard to say how these one-off challenges are impacting team success. For instance, the Braves are not 20-9 just because catcher Drake Baldwin has an eagle eye behind the plate, and Ben Rice is not sporting a 1.182 OPS solely because he has a robo-ump in his corner.

However, thanks to Statcast data, we can see which players and teams have been the biggest beneficiaries– and victims– of ABS in the small sample of April baseball we’ve seen.

Who needs a frame?

Many people (myself included) worried that ABS would decrease catcher value and make framing obsolete. Instead, certain catchers have begun to separate themselves from their peers, and the data suggests that strength in framing does not necessarily correlate to good ABS challenges.

In 2025, the top five catchers in Catcher Framing Runs were Patrick Bailey (25), Alejandro Kirk (17), Austin Wells (12), Austin Hedges (11) and Cal Raleigh (7). Of those players, only Raleigh is top-ten in Net Runs For on challenges behind the plate. Hedges has been solid (0.4), and Kirk has dealt with injuries, but both Bailey and Wells find themselves well below average on productive challenges.

The best backstops in this category have actually been two veterans– Salvador Perez and Carson Kelly. Perez has a 79% success rate on 24 challenges, and has actually flipped two strikeouts and three walks in favor of his pitching staff. Kelly is the only catcher with a better Nets Run For than Perez (1.8 to 1.6), thanks to his 86% success rate and five flipped strikeouts. Kelly is proof that more challenges does not directly mean more team success, either. The Cubs backstop has challenged just 14 times, tied for 24th in MLB.

The two most frequent challengers, White Sox catcher Edgar Quero and Brewers catcher William Contreras, actually have had a negative impact on their teams according to Nets Run For. Quero, who also ranked as the worst framing catcher in 2025, has lost 19 of his 32 challenges this season.

Good eye, kid

Hitters don’t challenge as often as catchers, given that they usually only take four to five at-bats on a given. Of course, nobody told Gary Sanchez or Jose Caballero that, as each has challenged 10 times with a 50% success rate in 2026. 39 hitters have challenged at least five times this season, with the median success rate also sitting at 50%. Pete Alonso leads all players with five-plus challenges with an 83% success rate, also earning him a 1.1 Nets Run For score.

Similar to defensive challenges, a high number of checks by a hitter does not correlate to a high Nets Run For. Riley Greene and Eugenio Suarez, who sit just behind Alonso with 0.9 Nets Run For scores, have each only challenged twice. Both times the two sluggers were successful, and better yet flipped a strikeout or gained a walk out of the challenge.

To determine whether a “good challenger” would have better overall success than a “bad challenger,” I narrowed my search to players with five or more challenges, then split those with a success rate of greater or less than 50% into two groups and compared OPS. The result?

The average OPS of a “good challenger” was about 30 points higher, but a scatter plot revealed that both sides of the spectrum experienced extreme variation in OPS. While it may have a minor impact, it’s unlikely that ABS success rate will be a strong evaluator for hitting talent.

Team effort

So which team is the best at using the ABS system? Which one is the worst? Does it even matter?

Much thanks to Perez, the Kansas City Royals stand atop the leaderboards as the best challenging team in the league– with success on 63% of challenges This alone almost discredits any potential claim that ABS is strongly influencing game results. Kansas City is an AL-worst 11-17, tied for last in its division.

The New York Mets and Chicago Cubs have the same success rate, but the Royals posted the best “Total vs. Expected” score, which Statcast describes as “nets overturn more than expected by a team seeing identical pitches.” Apparently, the Royals don’t just get overturns right– they do it better than any other team.

But, of top-10 teams in terms of challenge success rate, seven have a winning record, and one, the Texas Rangers, are 14-14. The only two teams with losing records are the Mets and Royals. So what about on the other end of the spectrum?

The Washington Nationals take the crown for winning the fewest challenges, succeeding on just 19 of 49. Others that have struggled include the Guardians, Giants, Braves and White Sox. From the bottom-10 teams in challenge success rate, half have winning records.

As the season progresses, it will be interesting to see if bad teams start to fall and stay towards the bottom of the leaderboard, and if division leaders will rise to the top. For the time being, ABS lessons won’t be replacing batting practice or bullpens anytime soon.