Commentary | Some umpires fear ABS is causing fans to judge them by near-impossible standards

Most businesses would balk at creating a system that subjects some of its employees to public embarrassment. But with its introduction of the automated ball-strike challenge system this season, MLB did just that to its umpires.

Some fans see the early results from the challenge system as proof umpires are incompetent. Some players and league officials say the opposite. But not all fans grasp the distinction between a call overturned by one-10th of an inch and one overturned by 2 inches. They just see that it was reversed.

Well, the challenge system is not perfect, either. I like it, as I wrote after the opening weekend. But I said then that it was in the shiny new toy phase, the robots at their most romantic. In talking to some umpires since, they have expressed reservations about the system.

The league said during spring training that the median margin of error on any given pitch in ABS is about one-sixth of an inch. That seems like a minuscule amount, but according to the website Tap to Challenge, 28 overturned calls through Monday -- an average of nearly three a day -- fell within that margin.

Some umpires, speaking on the condition of anonymity because both the league and their union want them to refrain from public comment, are quietly stewing. They say fans are judging them by a near-impossible standard and fear the game under the system will ultimately suffer.

Those umpires expect that pitchers and catchers will eventually grow angry that more balls are being called in the smaller zone, both by plate umpires and robots. The human zone was three-dimensional; the robot version is two-dimensional, hanging like a pane of glass across the middle of the plate. Many in the sport expected the redefined strike zone to increase the walk rate. So is it any coincidence that the combined 269 walks issued last Saturday and Sunday were the most to that point in any two-day span in the modern era?

Perhaps those two days were a small-sample aberration in the first month of the season, when hitters generally swing the least. Perhaps pitchers and umpires are simply adjusting to the new technology. Complaints from pitchers have been minimal. And pitchers say some umpires are fine with it, too.

Most fans are enjoying the system. It not only holds umpires more accountable, but also introduces new layers of strategy, making games more entertaining. Oh, and let’s not forget: The umpires agreed to ABS in their latest collective bargaining agreement, effectively letting the genie out of the bottle.

In exchange for their consent, umpires received concessions in other aspects of the deal, according to a person briefed on the details. The umpires did not extract the same type of “call stands” provision that exists in video replay review for other calls on the field, where challenges cannot be overturned without clear and convincing evidence.

The ABS equivalent would be a buffer zone allowing for calls within a specific margin of error to remain unchanged. Such a zone existed before robots. The league, in its internal evaluations, did not penalize umpires for calling pitches a strike that missed the plate but hit the buffer zone.

This system offers no such forgiveness. The league is steadfast about its accuracy. League officials have said MLB is 95% confident a pitch will be within 0.39 of an inch of the location the system says it is. The league also said it is 99% confident the location will be within 0.48 of an inch.

That’s not perfection. With the league affording the technology such a margin of error, umpires are justified in asking for their own accommodation. But when they brought the matter to the joint competition committee, their concerns were dismissed, according to one person briefed on the discussions.

The league’s argument is that a buffer zone would be impractical. Imagine, for example, a 3-2 pitch that is called a strike, shown to be a ball on the scoreboard graphic, then ultimately ruled a strike because it was in the buffer zone. Such an outcome would probably leave fans confused and upset. ABS is far more clear-cut. And the league, after putting the umpires in a difficult spot, says they are performing exceedingly well.

“Major league umpires hold themselves to the highest standard and deeply care about getting calls right,” Michael Hill, MLB’s senior vice president for on-field operations, said in a statement. “We appreciate the professionalism of our umpires and their commitment to the good of the game and the wishes of fans.”

Hill commended umpires for being accurate as a group. They had a 93.5% accuracy rate on pitches this year through Tuesday, up 0.8% from the same number of games in 2025 (92.7%). “We are also pleased that on the closest of pitches, those being challenged, umpires have been correct nearly half of the time,” or 46.2%, he said.

In future appearances, MLB Commissioner Rob Manfred should drive home this point. The data thus far shows just how precise the best umpires are. The average miss of the 11 most accurate umpires is 0.7 of an inch or less, according to Tap the Challenge. For the 40 most accurate, it’s 1 inch or less.

As in any profession, some umpires are better than others. But those who want the league to abandon the challenge system and go full ABS should heed the words of Baltimore Orioles pitcher Chris Bassitt, who values the skill of the umpires: “I don’t think people realize 0.2, 0.3 inches off the plate -- they’re like, oh, my gosh, I can’t believe you missed that call. Go get a ruler out, please, and realize how much they just missed it by. He barely missed it.”

He added: “These umpires are literally that good. I could not be more in favor of keeping umpires in this game.”

Still, some umpires worry. At every stadium, the league employs a ball-out-strike system operator who is responsible for ensuring the correct strike zone is used for each hitter -- so that 5-foot-11 Trent Grisham is not stuck with the zone of 6-7 Aaron Judge.

Some BOSS operators, like some pitch-clock operators, are hourly employees. Others are full time. The umpires wonder: Should hourly employees be holding the keys to the ABS kingdom?

Detroit Tigers pitcher Casey Mize, one of four player representatives on the competition committee, said he recently had a conversation with Bill Miller, the one umpire representative, asking him his thoughts on ABS.

“He has been in the league and hasn’t had any training with this, and that’s a problem,” Mize said. “The younger umpires have. But the older guys haven’t. They’re kind of doing the best they can.

“Unfortunately, social media is probably going to blow him up for it. Not just him, I’m saying all of them. Being in the league as long as they have, this is literally brand-new to them. They haven’t had a crash course on it outside of a few spring training games. But he said, overall, he thinks it’s a useful tool.”

Not all umpires agree with Miller. They are understandably sensitive to the criticism the system has unleashed, considering their degree of difficulty in learning a new system and new strike zone at the same time. None of the umpires mind when the system corrects their egregious misses. But when calls one-10th of an inch off are lumped into the same mistake bucket as those bad errors, the credibility of the system suffers.

As with most rules changes, unintended consequences were inevitable. It’s bad enough when a good umpire is made to look foolish. It will be worse if pitchers start growing exasperated over losing strikes. And far worse if a postseason game is decided by a reversal that, because of the margin of error, might have been flat wrong.

This article originally appeared in The New York Times.

Copyright 2026 The New York Times Company

This story was originally published April 11, 2026 at 4:34 PM.