MLB’s ABS Challenge System is exposing the worst umpire in baseball | The Verge
Overview
Tech Expand Amazon Apple Facebook Google Microsoft Samsung Business See all tech
Reviews Expand Smart Home Reviews Phone Reviews Tablet Reviews Headphone Reviews See all reviews
Details
Science Expand Space Energy Environment Health See all science
Entertainment Expand TV Shows Movies Audio See all entertainment
Policy Expand Antitrust Politics Law Security See all policy
Gadgets Expand Laptops Phones TVs Headphones Speakers Wearables See all gadgets
Verge Shopping Expand Buying Guides Deals Gift Guides See all shopping
Streaming Expand Disney HBONetflix You Tube Creators See all streaming
Transportation Expand Electric Cars Autonomous Cars Ride-sharing Scooters See all transportation
Entertainment Close Entertainment Posts from this topic will be added to your daily email digest and your homepage feed. Follow Follow See All Entertainment
Posts from this topic will be added to your daily email digest and your homepage feed.
Report Close Report Posts from this topic will be added to your daily email digest and your homepage feed. Follow Follow See All Report
Posts from this topic will be added to your daily email digest and your homepage feed.
Tech Close Tech Posts from this topic will be added to your daily email digest and your homepage feed. Follow Follow See All Tech
Posts from this topic will be added to your daily email digest and your homepage feed.
The ABS Challenge System is exposing the worst umpire in baseball
Posts from this author will be added to your daily email digest and your homepage feed.
SAN DIEGO, CALIFORNIA - AUGUST 09: Home plate umpire CB Bucknor looks on during the third inning of the game between the San Diego Padres and the Boston Red Sox at Petco Park on August 09, 2025 in San Diego, California. (Photo by Orlando Ramirez/Getty Images)
Posts from this author will be added to your daily email digest and your homepage feed.
During Wednesday’s game between the Tampa Bay Rays and the Milwaukee Brewers, umpire CB Bucknor took a foul ball to the mask and had to be helped off the field. It was the cap to what has been a particularly bad week for one of the most controversial umpires in baseball.
It started with perhaps the best example of how MLB’s Automated Ball-Strike (ABS) Challenge System can inject drama in baseball. This is the first year for the new robot umpire, which allows hitters, catchers, and pitchers to challenge balls and strikes for the first time. Each team starts a game with two challenges. But they only lose a challenge if it’s unsuccessful, so players aren’t inclined to demand a review unless they’re sure.
During Saturday’s game between the Red Sox and the Reds, Eugenio Suarez challenged Bucknor on back-to-back strike three calls and successfully had them overturned by the robo ump.
It doesn’t matter that Suarez ultimately grounded out. What matters is that, in a game where the Reds hit two home runs, the loudest cheers came for a pair of successful ABS challenges.
This was far from the only time that Bucknor had his calls overturned at the plate, it was a bad night for him overall. There were eight ABS challenges over the course of the game, and six of them were successful. The two calls that were not overturned were extremely close, within 0.1 inch of the strike zone edge. His misses, however, were more dramatic. Three pitches he called strikes missed by 2.4 inches or more — one was a full 2.7 inches out of the zone. And, by Jomboy Media’s judgment, Bucknor blew 20 calls if you count ones that weren’t challenged.
As the game progressed, you could see the exasperation on Bucknor’s face grow as the last five challenges were successful. The clear message from the robots was: you’re bad at your job. The league rate for ABS challenges is 55 percent overturns, but Bucknor’s rate stands at 78 percent as of April 2nd.
There were a couple of umpires whose first brushes with ABS went worse. Chad Whitson had all seven of the seven challenges in his game between the Yankees and the Giants on March 28th overturned. But while Whitson may have had a bad game, Bucknor has had a rough career.
According to measurements by Ump Scorecards Bucknor has been the least accurate umpire in Major League Baseball over the last five years by a significant margin. The site gives each ump an expected accuracy score and then measures how many correct calls above or below that they make. From 2020 through April 2nd of 2026, CB Bucknor is rated as being 253.74 below his expected number of correct calls — and his expected accuracy is not particularly high to begin with. Bucknor’s closest competitor is the nearly as derided Laz Diaz, who is rated as being 202.03 below the expected number of correct calls over an equal number of games.
Bucknor doesn’t need ABS to make him look bad, either. On Tuesday, he made what is clearly the worst call of the young 2026 season so far. He called Milwaukee’s Jake Bauers out for failing to touch first base on a groundball. The call was quickly overturned on review, but you didn’t need instant replay to know that Bucknor was wrong. The only way it could have been more obvious is if Bauers stopped and jumped up and down on the bag with two feet. The call was so egregious that both managers exchanged a knowing laugh from across the field.
Teams will obviously have to adjust to the new challenge system and develop strategies for how best to navigate it. But its biggest impact will be on umpires who are going to have to adjust to a more consistent and mathematical strike zone. Umpires like CB Bucknor who have had, let’s say a more subjective view of the strikezone, are going to have a rough 2026.
Terrence O'Brien Close Terrence O'Brien Weekend Editor Posts from this author will be added to your daily email digest and your homepage feed. Follow Follow See All by Terrence O'Brien
Posts from this author will be added to your daily email digest and your homepage feed.
Entertainment Close Entertainment Posts from this topic will be added to your daily email digest and your homepage feed. Follow Follow See All Entertainment
Posts from this topic will be added to your daily email digest and your homepage feed.
Report Close Report Posts from this topic will be added to your daily email digest and your homepage feed. Follow Follow See All Report
Posts from this topic will be added to your daily email digest and your homepage feed.
Sports Close Sports Posts from this topic will be added to your daily email digest and your homepage feed. Follow Follow See All Sports
Posts from this topic will be added to your daily email digest and your homepage feed.
Tech Close Tech Posts from this topic will be added to your daily email digest and your homepage feed. Follow Follow See All Tech
Posts from this topic will be added to your daily email digest and your homepage feed.
April Fools’ Day 2026: the best and cringiest pranks
Claude Code leak exposes a Tamagotchi-style ‘pet’ and an always-on agent
I tested a living room full of cheap Ikea speakers against Sonos and Bose
Key Takeaways
- Tech Expand Amazon Apple Facebook Google Microsoft Samsung Business See all tech
- Reviews Expand Smart Home Reviews Phone Reviews Tablet Reviews Headphone Reviews See all reviews
- Science Expand Space Energy Environment Health See all science
- Entertainment Expand TV Shows Movies Audio See all entertainment
- Policy Expand Antitrust Politics Law Security See all policy
