No, MLB players cannot challenge whether or not they meant to challenge. That decision, even with robots in the ascendancy, remains the purview of human beings. So amid the overwhelming success of the ABS challenge system’s first season, a minor, somewhat whimsical flaw has emerged.
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Umpires, it appears, are not always sure whether a player actually intended to challenge. And players, forced to make a complex decision within a two-second window, are not always clear in signaling for one. The result has been a relatively minor wave of accidental challenges, nearly all of which are caused by some flavor of miscommunication.
Part of this disconnect can be attributed to a lack of familiarity. Time will help iron out many of the wrinkles. As players and umpires get more acclimated to the new normal, the process will run more smoothly. Experience, for all parties, will bring clarity.
And 99% of the time, the process already works flawlessly. The aggrieved player taps their head. The umpire sees it and initiates the challenge via the stadium microphone. The animation flashes on the jumbotron and the call is either upheld or overturned. The game carries on.
But the challenge signal itself — a tap of the helmet or hat — has already been a culprit of confusion on many occasions. Players, it turns out, are touching their heads all the time.
(Josh Heim/Yahoo Sports)Recent examples of miscommunication over head taps
Here’s how MLB worded the rule during a spring training presentation to media. Under a section labeled “requirements for a challenge to be accepted” the guideline states that “batter, pitcher or catcher must tap their hat / helmet to challenge” and that “players are encouraged to simultaneously verbalize the request to challenge.”
That wording is key, as it puts the responsibility on the player to effectively communicate their desire to challenge. As we’ve seen, that’s not always what happens.
For instance, Shohei Ohtani adjusted his hat after throwing the first pitch of an April 8 game against Toronto. His catcher Will Smith appeared to mistake that action for a challenge request and immediately tapped his own helmet, resulting in a failed challenge. On April 12, Pittsburgh Pirates pitcher Bubba Chandler was awarded an unwanted challenge (which he ended up winning) for lightly tapping the back of his cap.
Well... this is a new one! 🫨
— SportsNet Pittsburgh (@SNPittsburgh) April 12, 2026
Bubba accidentally challenged a pitch by adjusting his cap, but he ended up winning it 🤣 🧢 pic.twitter.com/xM3mTUyqvO
There have also been multiple instances where hitters have moved a hand toward their helmet, as if to challenge, before changing their minds and pulling their hand away. Sometimes, umpires follow that last-second course correction and act accordingly. That happened during Saturday’s D-backs-Mets game when Arizona catcher Adrian Del Castillo reconsidered before touching his head.
The in-stadium scoreboard crew put the challenge on the big board, understandably confusing the broadcasters, but umpire Lance Barksdale never got on the microphone to announce the challenge.
The ABS challenge "pump fake" pic.twitter.com/NfXrpxnNPA
— FOX Sports: MLB (@MLBONFOX) May 10, 2026
The opposite happened to Orioles infielder Coby Mayo on April 15, when he pulled a move similar to Del Castillo, except home plate umpire John Tumpane awarded a challenge. The call was upheld.
In a recent conversation with Yahoo Sports, Mayo admitted that he initially considered challenging that particular pitch before changing his mind based upon it being a 3-0 count. He also explained that while he verbally disagreed with the call, he didn’t actually say the word challenge.
“So he saw me go towards the hat. And then I said, ‘That's a ball’, so I think he said those two things together means I want to challenge.”
Mayo doubled on the next pitch.
Umpire made Coby Mayo use this challenge, even though a camera angle shows he never touched his helmet pic.twitter.com/G81xlEL63i
— Jomboy Media (@JomboyMedia) April 15, 2026
How did the hat tap become THE signal in MLB?
The hat-tap as baseball’s now-ubiquitous challenge signal has a relatively boring, humble origin story. MLB first implemented the ABS challenge systems in the Low-A Florida State League in 2022. The league had already experimented with full ABS — umpires calling all pitches via the system — in the independent Atlantic League in 2019. But the challenge system presented an interesting new wrinkle: how would players actually signal to umpires?
For the committee tasked with implementing the new system, none of the existing gestures were satisfactory.
By that time, the hands-over-ears "headphones" move was well known around the sport as the choice signal for big-league managers requesting a challenge. But players rarely have both hands free, making that gesture difficult to do. The NBA uses a one-handed circular whirling motion for its challenge system, a motion that baseball has used as its home run sign for decades. That wouldn’t work.
Both the NHL and professional tennis utilize a verbal-based system. That would have made sense practically, but would have been immensely difficult for a viewer at home or a fan at the ballpark to see. The league wanted the arrangement to be intuitive and entertaining.
A league spokesperson confirmed to Yahoo Sports that at no point did the league consider an NFL-style challenge flag system, the sort that former MLB player Justin Turner pined for on the internet earlier this year.
The head tap for a challenge is already becoming a disaster for “accidental” challenges. I vote for everyone to have a yellow hanky in their pocket and you have to throw it like an NFL ref to initiate a challenge. What do you think??
— Justin Turner (@redturn2) April 13, 2026
In fact, there was relatively little deliberation inside the league office about the hat tap. Officials were, understandably, more focused on a plethora of complex mechanics related to the challenge system. Somebody brought up the hat tap as an option, enough others thought it reasonable and voted it through. It was instituted for the 2022 Florida State League season and league officials figured they could reevaluate if there were any major issues. There weren’t.
And so, the head tap endured, somewhat inadvertently becoming an omnipresent, universal signal in the world of baseball. Little leaguers all across the world are going to be tapping their hearts away all summerlong, if they aren’t already.
Big leaguers, despite the occasional confusion, don’t really mind the signal. They see it as an imperfect solution, better than any goofishly dreamt-up alternative. Some want a verbal component to be required alongside the head-tap. Others shrugged and said the status quo was fine. That’s probably how the league feels at this point. It has bigger fish to fry. The signal works most of the time. People like the challenge system. The occasional kerfuffle is simply the cost of doing business.