Automated umpire system earns high marks from Charlotte Knights
Hanging above the press box window at Truist Field is a jet-black square. It looks like a solar panel, but instead of catching rays, it’s been tracking balls and strikes since April 2022.
Enter the Automated Ball-Strike system (ABS). Half of all Triple-A games are now called by these pseudo-robots — also known as “robo umps” — that use computer-generated strike zones modeled after strike zones of high-level umpires. The other half of Triple A games are called by human umpires with a challenge system, where ABS is used only if a call comes into question.
Such reliance on technology might cause folks to disbelieve the system’s claimed accuracy — which Major League Baseball says is to less than one-tenth of an inch — but its quick ascendance to the highest level of the minors indicates it has been a net positive.
“I feel like my zone has gotten a lot better,” said Charlotte Knights third-baseman Laz Rivera. “I feel like with the ABS you can stick to your planes and secure your approach because you know balls are going to be balls, strikes are going to be strikes.”
ABS was first implemented in the minors in an independent Atlantic League all-star game in 2019. That same year, it was used in the Arizona Fall League before some Class A parks adopted it after the COVID-19 pandemic. Now, ABS has jumped to the highest level of the minor leagues.
Charlotte has been using the ABS system since the beginning of the 2022 season. It was the only Triple-A East team to do so along with the 10 teams representing the Triple-A West. In 2023 all 30 Triple-A ballparks are using ABS.
Thanks to TrackMan, the Danish-based golf startup responsible for ABS technology, the strike zone is set in stone. The top is set at 51% of a player’s height and the bottom at 27%, its width marked at 17 inches — the width of home plate. Within those dimensions, the zone forms a two-dimensional plane rising above the plate’s horizontal midpoint.
It’s consistent, which is one of the goals emphasized in the MLB’s original March 2022 statement. Along with eliminating an inconsistent strike zone, it serves to prevent games from turning on bad calls and eradicates human error.
“A lot of guys have said it’s been pretty accurate. If anything changes, it’s usually side to side,” said Knights hitting coach Cam Seitzer. “I think it’s great for them, full ABS, for them to understand the zone.”
The challenge system, however, has begun to rise as the more popular option over full ABS.
On Tuesdays through Thursdays in Triple-A, the umpire is simply relayed the calls made by the ABS system. Fridays through Sundays, each team is given three challenges per game and only then is ABS used to make the call.
This mitigates one of the bigger fears those in baseball hold when it comes to automated umpiring, which is the elimination of the human element of the game. Not only does full ABS completely remove this, it also removes credit from today’s home-plate umpires who were measured at 97.6% accurate last year.
“I’m more of a fan of a challenge system, just because it keeps the feel of the game,” Rivera said. “With the ABS it kind of takes it away from the umpire. With the challenge system, everybody is kind of locked in.”
Adding the challenge system also brings another element to the game — teams have to use strategy to choose when to use their challenges, especially considering they are only retained when correct. Challenges can also only be issued by the pitcher, catcher and hitter, allowing players to have more control over the outcome.
In an article by The Athletic, MLB Commissioner Rob Manfred hinted that he favors the challenge system over the full ABS approach. Similar to instant replay, he says, challenges allow players to “fix the big miss,” in the chance an umpire makes an egregious call.
“Moving forward and potentially at the next level, if they think about using it, I would say the challenge system, it’s more solidified as a whole, and they can choose their times that they feel like the umpire might have made a mistake,” Seitzer said.
Critics of the system believe the consistent strike zone minimizes framing — a common technique used by catchers where they receive the ball in a way that makes it more likely the umpire will call a strike.
Pitchers as well are having to adjust because the ABS strike zone isn’t called the same as an umpire will call it. There are parts of the strike zone an umpire won’t call because they’re virtually unhittable. ABS, Manfred said, doesn’t account for that.
Earlier this month, Manfred said the ABS system won’t likely make it to the major leagues in 2024, according to The Associated Press. Still, it’s rapidly evolving. Just as both positions have had to modify their defensive strategies in the minors, so too will they at the next level.
“We knew ABS was coming. So right now, the most important thing is catch the ball. Where you catch the ball, that will dictate if it’s a strike or not,” said Knights catcher Sebastian Rivero. “That framing part, it won’t matter as much as blocking and throwing guys out.”
The purpose of ABS is simple: create a consistent strike zone from park to park and umpire to umpire.
Growing pains are inevitable with change, but so far, the response to ABS has been overwhelmingly positive in Triple-A, especially with regards to the challenge system — a trend MLB is tracking data on to help make its decisions about implementing the system in the future.
“It gives catchers a better idea of what the strike zone is, it gives the hitters and pitchers a better idea as well,” said Knights team manager Justin Jirschele. “You get a better grasp of guys that have a really good understanding of the strike zone.”
This story was originally published June 28, 2023 at 7:00 AM.
