TheAthletic: The robot umps are here: What to watch for with ABS this MLB spring training

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# The robot umps are here: What to watch for with ABS this MLB spring training
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How will it work?

This is the easy part. The rules will be the same as the ones used in Triple A and in big-league spring training last season. Each team gets two challenges per game. If it gets a challenge right, it keeps that challenge. If it gets that challenge wrong, it loses a challenge.

Only hitters, catchers and pitchers have the power to challenge — and they need to do that within two seconds of the umpire’s call. They’re being told they have to both tap their head and verbally challenge so there’s no confusion.

Won’t this slow down the games?

The technology is so quick and efficient that each challenge delays a game by only about 15 seconds, according to MLB. Since the average Triple-A game last year featured four challenges, the league is estimating that this robot work will add only one extra minute per game. But here’s an informed guess:

We’ll have many, many games in the big leagues this year with more than four challenges. I’ve heard too much talk this spring (already) of teams telling their players: Use all your challenges!

So when I think about how many catchers will have a challenge in their pocket with two outs in the ninth, I’m pretty much guaranteeing a game-ending, um, what exactly: A “tap-off”? A “gawk-off”? A “squawk-off”? A “robot-off”? Can’t wait for that.

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Are there times when teams can’t challenge?

There are, in fact. A team can’t challenge if a game is so out of hand that a position player is pitching. A team can’t challenge (obviously) if it’s used up all its challenges. And most importantly, an umpire can disallow a challenge — for two reasons:

1) If the hitter/catcher/pitcher takes too long to tap his head. Remember, these challenges are supposed to happen within two seco What’s a strike (in 2026)?

In theory, the strike zone has always been a fixed rectangle that stayed roughly the same every day, no matter who was hitting, pitching or umpiring. But in reality? Ho, ho, ho. That’s never been true.

A visualization showing the ABS strike zone compared to the one called by human umpiresCourtesy of MLB

That oval represents what human umpires most often called a strike in 2025. That rectangle is the actual ABS zone. You can easily see those two things are not the same.nds of the umpire’s call.

2) Most importantly, an umpire can rule that the player had “help” in making that “instantaneous” decision and deny the challenge. So here’s another prediction: That’s going to be a thing.

Think of all the managers and coaches who have spent their whole careers, screaming at umpires after every pitch: C’mon, that ball’s low. Or: That’s a freaking strike. Or other more colorful stuff you won’t be hearing on “My Little Pony.”

If an umpire thinks that a challenge was inspired by that kind of talk, he can refuse to allow it.

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One thing it will help with is when pitchers throw a strike but miss the intended location. You see that often where a catcher is set up inside but the pitcher misses the location. The ump usually calls it a ball even when it was still in the zone.

Same thing goes for the Greg Maddux strikes where he hits the catchers glove perfectly but it’s 3 or 4 inches off the plate and called a strike. Some control pitchers may have to alter the way they pitch a little

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. It’s 50/50 overall, but fielders are better at this than batters.

In Triple-A in 2025, the overturn rate was almost exactly 50%. Batters weren’t as good (45% success rate) as fielders (nearly 55%). (As for what specifically we mean by “fielders,” more on that below.)

Those numbers correlate reasonably well with what we’ve seen in the first few days of 2026 Spring Training – the overturn rate is 52%, and batters aren’t as good (48% success rate) as fielders (55%).

That’s intuitively expected. Catchers can take the long view of the game more than hitters, who have only brief times at the plate to challenge, and catchers are crouching with a similar view of the zone as the umpire.

Don’t gloss over the importance of the 50/50 success rate, though: If these challenges are going to come only on pitches close enough that you think the umpire was wrong, and it’s still only a 50/50 shot that the player is correct, well, that has to say something really good about how well umpires do their job – which is far, far better than the credit they’re given. Remember that unlike umpires, who must call everything, challenging players can cherry-pick good opportunities – and they’re still only right half the time.

Fielders, for now, includes both the catcher and pitcher, either of whom is allowed to challenge, simply because the way the Minor League data was collected didn’t specify who initiated it. At the Major League level, at least, expect that to be overwhelmingly backstops, at least the way managers are talking.

Chris Sale, notably, has already said that he’ll never take advantage of initiating a challenge. “I fully agree with him,” said San Diego starter Michael King.

“My early thought … I don’t think the pitchers should ever challenge,” Twins skipper Derek Shelton said to ESPN, and Astros manager Joe Espada said, “I highly encourage [pitchers] not to do it.” On the other hand, Yankee manager Aaron Boone seemed open to letting his hurlers try.

We’re guessing there will be a few – but not many.

2. Relatively few pitches get challenged.

If you’re worried this is going to take over the game, don’t be.

Last year in Triple-A, there were just over 861,000 pitches. On them, there were 9,432 challenges, which means that slightly more than 1 percent of all pitches resulted in a challenge. Since the overturn rate is roughly 50/50, well, 0.5% of all pitches ended up being overturned. That’s really not very much.

Of course, not every pitch is a challengeable one. You can’t challenge a swing, for example. You can’t challenge if you’ve already used up your challenges and have no more available. You’d never want to challenge if the call went your way, obviously. You’d never bother if it went against you and was clearly correct.

Among challengeable pitches – non-swings that went against you, with challenges remaining – it was still only 3% of the time that the hands would tap the helmet. If you’re just looking at takes on the edges of the zone, it was under 7% of pitches that got challenged. The reason why is clear: because so many borderline pitches are borderline enough that it’s not obvious to risk the challenge.

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That there’s only 2 challenges available also limits its usage, as you want to save them for high-leverage situations. There’s no point challenging when you’re down 7-1 in the 7th inning with two outs and no one on base.

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You keep the challenges if you are right though. I saw a training camp game had like 8 or 9
challenges the other day.

For example