PARADISE VALLEY – Like it or not, more change is coming to Major League Baseball.
The Omni Scottsdale was packed with managers, front office executives and journalists for Cactus League media day Thursday. A popular topic of discussion was the Automated Ball-Strike Challenge System, which the league will implement for the 2026 regular season.
Joe Martinez, vice president of on-field strategy at MLB, spent the final 30 minutes of the event presenting a slideshow on the change. The system, which has been tested in the minor leagues since 2019 with the independent Atlantic League, an MLB partner, and later the Arizona Fall league, will allow pitchers, catchers and batters the opportunity to challenge balls and strikes on major league fields during the regular season for the first time.
“We get a lot of feedback from fans and media and players on that, we’re like ‘tinkering with the game,’” Martinez said. “It’s not our intent. What we are trying to do is address some specific areas where we think there’s opportunities.
“There’s issues that we think we can redirect and fix a little bit.”
The goal of the ABS Challenge System, as noted on one of the slides, is to “provide players with an opportunity to correct missed calls in high-leverage moments in a manner that fans like.”
Only time will tell how that looks over the course of the season, but many around the game are ready for ABS’s implementation.
“MLB does a really good job of not throwing stuff against the wall and hope it sticks,” Cincinnati Reds manager Terry Francona said. “They go to the minor leagues, they go to independent ball and then they explain it to us very well. … It’s going to be OK.”
Teams will have two ABS challenges to use over the first nine innings, and the challenges can only be initiated by a pitcher, catcher or batter – signified by tapping their head immediately after the home plate umpire’s initial call – and have to be called without any assistance from a manager, coach or teammate.
One interesting element of the ABS Challenge System is that teams that enter a new extra inning without a challenge will gain one. For example, if a team has no challenges entering the 10th inning, it would be given one, and if it lost that challenge in the 10th, but the game went to the 11th, it would gain another challenge. If that team won its challenge in the 10th, it wouldn’t gain a challenge for the 11th, as it would have retained its challenge.
This subsection of the rule was added for the 2026 season after feedback from players and on-field personnel.
“The idea is teams are kind of budgeting for nine innings of play,” Martinez said. “Bonus baseball, if you’re out of challenges, you get one more.”
If a player’s challenge is successful – which MLB’s data shows happens approximately 51% of the time – the team retains the challenge, but if it fails and the ruling on the field is upheld, the challenge is lost. If a team loses two challenges before the completion of a game, it will be unable to challenge any more ball-strike calls.
Teams are still working on strategies for how they want to use the system, but different philosophies are already emerging. Athletics manager Mark Kotsay is allowing his players to “police themselves” in regards to using the system, while other organizations like the San Diego Padres are taking a more hands-on approach during spring.
“It’s going to be something that we spend a lot of time on in spring training,” said general manager A.J. Preller, the Padres’ president of baseball operations. “Trying to make sure our players and our staff understand leverage situations, when to use it, who to use it with.”
Who will be given the green light to use the system is something that’ll be interesting to watch as spring training and the season unfold. Craig Stammen, a former big league pitcher for parts of 13 seasons who Preller hired to be the new manager of the Padres, said players’ opinions can often be skewed.
“I remember pitches going in the zone, and me thinking ‘That’s for sure a strike, how’d that umpire not call that?’ And then looking on video and it not being a strike,” Stammen said. “Sometimes a pitcher, our view of what the strike is, is a little clouded.”
One of the more intricate changes to the rule is that umpires can use their discretion to determine at what base a runner should be placed if an incorrect ball-strike call was made and ultimately overturned while that runner was performing an action.
Martinez highlighted an example from the minor leagues where a runner on first attempted to steal second while the batter was in a 3-0 count. The pitch was initially and incorrectly called a ball, and the catcher, who still tried to make a throw down to second, dropped the ball.
The runner on first would’ve made it to second base, even if the pitch was initially called a strike, since the catcher dropped the ball. Under the old rules, because the call on the field was overturned to a strike, the umpires sent the runner back to first base. Now, if the same situation presented itself, the umpires would have the ability to let the runner stay at second base.
To gain a holistic understanding of the system, many big league managers are conversing with minor league coaches and players who have already built an understanding of the ABS Challenge System through their own experiences.
San Francisco Giants first-year manager Tony Vitello, who’s making the jump from the college game where he served as Tennessee’s coach, is leaning on a number of former big league managers to help him get his footing, but he is also talking to his first-year big league pitching coach Justin Meccage, who coached in Triple-A with the Milwaukee Brewers in 2025, about the system.
“It’s a conversation we’ve had on multiple occasions,” Vitello said. “I’m sure it’s the same for other clubs, too. Like everyone, it’s going to be a learning experience.”
Instances when managers won’t have to worry about the ABS Challenge System include when a position player is on the mound. However, that’s not the final quirk, as the MLB strike zone has now been redefined due to the rule’s implementation.
“The strike zone was probably the hardest question that we had to answer when testing the system,” Martinez said. “We think we’ve settled at a pretty good place, but it has definitely changed from what we’re used to.”
In the 2025 MLB rulebook, the strike zone is defined as: “that area over home plate the upper limit of which is a horizontal line at the midpoint between the top of the shoulders and the top of the uniform pants, and the lower level is a line at the hollow beneath the kneecap. The Strike Zone shall be determined from the batter’s stance as the batter is prepared to swing at a pitched ball.”
With ABS, the determining factor for each player’s unique zone is their height while standing upright. The top of each player’s zone will be 53.5% of their height, while the bottom end will be 27%. Every player will be measured in spring training to ensure the accuracy of their height and zone.
As for how the zone is situated, it’s a 2D rectangle positioned in the center of the plate, 8 1/2 inches from its top, and 8 1/2 inches from its pointed bottom. Width-wise, it’s 17 inches wide, just like home plate.
When the zone was tested in spring training last year, it was deemed “generally acceptable” to players.
“We tested all different kinds of things,” Martinez said. “A 3D zone, or setting it at the front, led to some odd strike calls in a way. You can envision a slow 12-6 curveball just clipping the bottom corner, and the catcher would catch it kind of towards the dirt, and that would be called a strike. Moving that zone back more in line with where the hitter is led to results that were more in line with expectations.”
MLB hopes that one of the changes that can be brought about by the redefined zone is an increase in walk rate. Strikeout rates have risen steadily over the years, but walk rates haven’t. In fact, walk rates have remained remarkably frozen between 7.6% and 9.6% over a 70-year period.
One thing that has thawed in recent years is the length of games following other rule changes, such as the pitch clock. MLB made sure that the ABS Challenge System wouldn’t undo any developments in that department.
The average time that challenges have added to Triple-A games is only one minute, eight seconds, and it was just 57 seconds when MLB teams had access to the challenge system in spring training last year.
It was the experience in spring training a season ago that gave many fans and players their first glimpse into an ABS world, and many in both camps, but especially fans, discovered that the system was one that they actually enjoyed.
“In spring training last year, we actually put a QR code up on the Jumbotron, and fans could scan it with their phone and provide feedback,” Martinez said. “When providing that feedback, 72% of fans said that ABS actually improved (their experience).”
While ABS has a sky-high approval rating, MLB admits it’s not quite perfect.
Last spring, there were four pitches out of 88,534 that weren’t tracked and five instances out of 1,214 total challenges where the animation showing whether or not the pitch was a ball or a strike failed to play on a scoreboard.
MLB has established procedures for handling those issues – and others – if they arise.
If a pitch is tracked but the challenge isn’t displayed on the scoreboard, the results of the challenge will be verbally communicated from the ABS operator to the home plate umpire, and if the pitch wasn’t tracked, the call will automatically stand and the team that challenged the call will retain its challenge.
If there’s a larger technical issue and ABS is down for an extended period, the game will resume without ABS, and it will be reintroduced as soon as it’s available again. MLB doesn’t believe teams gain or lose an advantage by reinstating the system during an existing inning or even at-bat, as both teams have equal ability to challenge, so long as they haven’t burned through their allotted number.
The league also recognizes that teams might be tempted to cheat the system, which is why it has installed safeguards, such as mandating that broadcast feeds that include the strike zone box and pitch-tracking data be delayed by at least nine seconds.
The biggest impact that ABS could have on the game could be at the catcher position. In baseball, catchers try and “frame” pitches, attempting to trick the umpire into making a ball look like a strike. With the challenge system, the importance of framing will surely change, but many can’t say to what extent.
“There’s a chance it’s not as much as you think,” Vitello said. “We don’t know the answer to that; a lot of it is very vague.”
Catcher framing runs is a stat that measures the runs saved or lost by a particular catcher’s framing ability over the course of a season, meaning it will eventually be possible to find out exactly how ABS impacts the skill. ABS will also more than likely bring about new statistics, as teams will want to know how good different catchers are at using the challenge system.
“We’re trying to measure everything, trying to gain every possible advantage,” Preller said. “If there’s something there that any team feels like can give you an advantage to win a baseball game, I think teams are going to try to capture it.”
Even with all its intricacies and lack of perfection, MLB is confident that ABS will improve the game in a meaningful way, and, just as importantly, the change isn’t receiving much pushback.
“We haven’t always gotten some player support of changes we’ve made on the field,” Martinez said. “It’s pretty nice when we can have something that we both feel is a good add to the game.”
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