ABS system

Ooh, Apparently The New ABS Challenge System That Stops Umpires’ Wrong Ball and Strike Calls From Changing The Outcomes Of Baseball Games Has Hurt Umpires’ Feelings…

/ Jack Marshall / 6 Comments

Tough. Do your job better.

The major MLB baseball rules addition this season, and one that is, as I so sagely predicted many years ago, both popular and beneficial to the game’s integrity, is the ability of players to challenge ball and strike calls instantly and have a computer image almost immediately appear that either confirms or overturns the home plate umpire’s call immediately. The results of many games have already been affected by the new technology. Of course umpires hate it, especially bad umpires, like the infamous Angel Hernandez, who is an embarrassment to the game. For the best umpires, the system is mostly beneficial, because it shows how accurate they are. Umpires in general have tightened up their pitch calling because of the technology. In the past, they used to defiantly talk about “my strike zone.” The ABS system makes it indisputable that there is just one strike zone, and that’s the one in the rule book.

In yesterday’s game between the Washington Nationals and the Boston Red Sox in Fenway Park, Boston’s best hitter, Willson Contreras, was called out on strikes after the first base umpire Nick Lentz ruled that his attempted check-swing had indeed crossed the plate. That call is (currently) unappealable and entirely within the umpires’ discretion. But as Contreras walked away from the plate to the dugout, he tapped his helmet in the manner in which a player signals that he is challenging a ball or strike call. Lenz threw him out of the game.

Contreras and Red Sox manager Chad Tracy were shocked, and came out of the dugout to argue against the ejection. Red Sox broadcasters were initially confused, since Contreras hadn’t said anything to the home plate umpire. (There are a few “magic words” that will guarantee a player’s exit). Then they saw that the video showed Lentz indicating the ejection and tapping his head to explain why.

“I called him out on appeal for the check swing, and as he was walking back to the dugout, he started gesturing, tapping his helmet, like he wanted to challenge something that is not a challengeable call,” Lentz explained to reporters. “And so [it was] disrespect, and again gesturing towards what he thought was an incorrect call, got him removed from the game.” The umpire claimed that it is an automatic ejection if a player makes that gesture in a mocking way. “It’s a lot like drawing a line in the dirt,” Lentz said.

No, it’s really not. Players standing at the plate and drawing a line to show how far a ball was out of the strike zone was obviously an attempt to show up an umpire and always resulted in an ejection, as did a batter curling his fingers around his eyes to say “you need glasses.” Those gestures neverfhappen any more, because the computer settles the issue. Most fans in the stands didn’t even notice Contreras’s gesture, nor did TV viewers, because the camera wasn’t on Contreras when he tapped his helmet.

Lentz added the gesture is “on the list for items for removal from the game.” If it is, I can’t find it, and if there was a memo, the players didn’t get it. Here is the current criteria for an umpire ejecting players:

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How’s That Computer Strike-Calling System Working?

/ Jack Marshall / 10 Comments

My verdict: it’s an improvement over relying entirely on the fallible home plate umpires, but ethical problems remain.

The current system gives each team two challenges if they think a ball or strike call is wrong. The teams can keep challenging as long as the ABS (Automated Ball and Strike) system backs their judgment. If a challenge proves mistaken, the team loses the challenge.

We have learned that knowing when a ball or strike call is wrong from the players’ perspective is harder than it looks. A few players are really good at it, but most are not. Because the prospect of a key pitch call being blown at a crucial juncture late in the game when the victimized team is out of challenges looms large, players have become increasingly reluctant to challenge pitches early in a game.

Ironically, the system takes accountability from umpires in some cases. In a recent Red Sox game, Boston’s opponent was out of challenges. In the 7th inning with the game close, a 3-2 pitch was called out of the strike zone, and Boston’s batter walked to first base with two outs. The pitch was, in fact, a strike, and should have ended the inning. Instead, the Sox had a long rally, scoring six runs. The announcers harped on the fact that it was the miscalculations of the losing team in using up their two challenges that opened the floodgates, but that’s not why the team lost. The team lost because the umpire blew the call, and it’s his job to call pitches correctly.

This situation, and there have been many of them so far this season, convinces me that players should not have to challenge bad calls, and the results of games should not depend on whether an umpire’s botch is challenged or not. The ABS system knows when a ball is in the strike zone with every pitch. If an umpire calls a ball a strike or vice-versa, the bad call should be instantly overturned without having to be challenged.

Baseball Ethics: More ABS Notes [Corrected]

/ Jack Marshall / 20 Comments

The major ethics issues animating discussion early in the baseball season are arising from the new computer ball and strike calling system, or ABS. Each team begins with two challenges. A batter, pitcher or catcher may challenge any strike or ball call at home plate, but must do it immediately by announcing “Challenge!” and touching his cap. Challenges that are made after two seconds elapse may be disallowed by the umpire. If a challenge results in a changed call, that challenge is preserved. If not, it is lost.

Already, game results have been affected by the rule. That’s not a surprise at all. Major League Baseball (MLB) umpires miss an average of about 10 to 15 calls per game; the overall accuracy rate was around 92%. in 2025. Every game generally includes at least one incorrect call, and it is estimated that 8.5% of all games have bad calls that alter the score. The accuracy of the umpires has increased since computers started double-checking them, but umpires still made 26,567 incorrect ball and strike calls during the 2025 MLB regular season, and any one of them might have altered a game’s outcome. Some early results:

1. The younger players are better at challenging than the veterans, because the system was used in the minor leagues the last couple of years. Red Sox player Trevor Story was called out on strikes on a pitch that looked well out of the strike zone, but didn’t challenge. Sox TV color man Lou Merloni, an ex-player, said that after a career of thinking that an umpire’s call was final, veteran players are likely not to remember that they could challenge until the two seconds have passed. Now players are being criticized for their strike-challenging skills.

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The Umpire’s Wish

/ Jack Marshall / 7 Comments

As explained here, this baseball season the new ABS system is in play, meaning that batters, catchers and pitchers can challenge ball and strike calls by the home plate umpire and have an electronic plate coverage system instantly reveal if the call was correct or wrong. No longer does the ancient rationalization protecting umpires who have botched crucial pitch calls provide cover: “The pitch is what the umpire says it is.” Not necessarily.

During a spring training game in Scottsdale, Arizona, the San Francisco Giants were leading the Cleveland Guardians 3-0 in the fourth inning. Giants pitcher Robbie Ray faced Guardians third baseman Alex Mooney with two outs and runners on first and second. After Mooney took an 0-2 sinker that home plate umpire Bill Miller called a ball, Giants catcher Patrick Bailey tapped the top of his helmet to signal for a challenge.

“San Francisco is challenging the ‘ball’ call,” Miller announced to the crowd on his microphones. Then the crowd heard him say, “Please be a strike!”

The ABS system confirmed that the pitch was a ball, as Miller had said. The guessing is that the umpire wanted his call to be over-turned because the temperature was over 100, this was a meaningless exhibition game, and he, like everyone else, wanted to get out of the sun.

That raises questions about the integrity of umpires, though maybe not Miller’s, who called the pitch a ball even though a strike might have allowed him to escape the heat sooner. His ad lib also could have been interpreted as a sign that he wanted the Guardians to win, except that nobody cares who wins Spring Training games. Even gamblers don’t bet on them.

The incident brings up a question about the challenge system that I have been musing about lately: why can’t umpires challenge their own calls?

I agree that you don’t want to have umpires second-guessing their pitch calls, saying, “Steee-rike THREE!…well, wait a minute…I think that was a ball. Yeah, let me change that. Ball three.” But former players all have anecdotes about umpires confessing to a batter or a catcher after a missed call, “Yeah, I missed that one.” If an umpire thinks his call was wrong, why shouldn’t be get to challenge his own call?

A Brief But Trenchant Baseball Ethics Note…[Updated]

/ Jack Marshall / 2 Comments

Above you can see the final pitch of the USA-Dominican Republic semi-finals last night in the ongoing World Baseball Classic. That 2-out, 9th inning pitch was called a strike on a 3-2 count, meaning that the Dominican shortstop Perdomo was out, and the U.S. had won a tight 2-1 victory sending it into the championship game against either Venezuela or surprise “Cinderella” squad Italy.

Winning is nice; winning legitimately is better. That pitch was a ball, as you can see. if the umpire had called the pitch correctly, Perdomo would have advanced to first, and the DR’s best player in the tournament, Fernando Tatis, would have come to the plate with the tying run on third base and the winning run on third.

In the 2026 MLB season that starts soon, the new ABS system will be underway. After a botched call like that one, the batter will touch his cap and say “Challenge!” and the image of where the pitch was relative to the strike zone will flash on a screen, showing that the umpire was wrong, reversing the call.

No baseball game, especially an important one, should end on a terrible call like the one that eliminated the Dominican Republic team. If this doesn’t convince the bitter-enders and “traditionalists” who oppose getting ball and strike calls right when the technology exists to do so, nothing will.

UPDATE: ESPN’s Jeff Passan just posted,

“That was a wonderful baseball game. Tension. Drama. Passion. Pride. Everything baseball can be. Everything you want baseball to be. So, for it to end on a called strike three by home plate umpire Cory Blaser on a Mason Miller slider that was clearly below the zone was such a gut punch, not just to the Dominican Republic players, whose country cares more about the WBC than any, but to a game that deserved better. ABS cannot come soon enough because this should be about the quality of the game, which was tremendous, and not the bitter taste left due to human fallibility.”

Robo-Umps Are Officially In Major League Baseball, and It’s An Ethical Development

/ Jack Marshall / 15 Comments

Finally, Major League Baseball has conceded that with technology available to call balls and strikes accurately, it makes no sense to permit bad calls by human umpires to change the results of at-bats, games, careers and even whole seasons. In 2026 the “ABS” system will be in play, adding integrity, accuracy and, yes, strategy to the game. Good. It’s about time.

I’ve been advocating computerized ball and strike calls at least since 2017, when I wrote,

In the top of the eighth inning of a crucial Dodgers-Cubs NLDS game, Dodger batter Curtis Granderson struck out. The pitch hit the dirt, and Cubs catcher Willson Contreras, as the rules require when a strike isn’t caught cleanly, tagged Gunderson for the final out of the inning. Granderson argued to home plate umpire Jim Wolf that his bat had made slight contact with the ball. It didn’t. The replay showed that his bat missed the ball by at least four inches. Nonetheless Wolf, after conferring with the other umpires agreed that the ball was a foul tip. Gunderson’s at bat was still alive….

After the game, Wolf watched the video and told reporters that he had indeed, as everyone already knew, blown the call.

As it happened, his embarrassing and needless botch didn’t matter. Gunderson struck out anyway. That, however, is just moral luck. The call and the umpire’s refusal to reverse it was just as inexcusable whether it resulted in ten Dodger runs or nothing. The point is that such a call could have changed the game, and the series. If it had, the screams from Chicago fans and anyone who cares about the integrity of the game would have persisted and intensified until baseball abandoned its archaic rationalization that “human error is part of the baseball,” and made use of available technology to make sure such a fiasco can’t happen.

This scenario will occur. Human beings being what they are, however, it won’t play out until a championship has been lost after a strike three right down the middle of the plate is called a ball by a fallible human umpire, and then the lucky batter hits a game-winning, walk-off grand slam on the next pitch. Then, after the horse has not only fled but trampled the barn-owner’s children, Major League Baseball will put a lock on the door.

The barn door, however, is wide open now, and the lock is available.

Two years later, I complained about this foolish attitude by the baseball powers- that-be again, writing,

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Moral Luck and Baseball: The High-Profile Ruinous Ball-Strike Call Comes AFTER The Problem Has Been Addressed

/ Jack Marshall / 11 Comments


Next season, Major League Baseball will implement the Automated Ball-Strike (ABS) Challenge System. For the first time in regular-season history, batters, catchers and pitchers will have the right to challenge balls and strikes. Teams will begin each game with two available challenges and can continue challenging until they lose challenges twice.

The system has been desperately needed for many years, ever since each player’s strike zone could be seen on television screens during game broadcasts. As usual, baseball dragged its metaphorical feet addressing the problem, with the idiotic “bad calls by the umpire are part of the game” argument that traditionalists and ex-players are still using. That logic makes as much sense as defending medical malpractice because “everyone makes mistakes.” Sure, before video technology could prove a key ball or strike call was a bad one, tolerating home plate umpire mistakes (like the one that cost the Boston Red Sox Game 3 of the 1975 World Series and conceivably the Series itself) were part of the game, because nothing could be done about it. Now something can.

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