Will MLB's ABS challenge signal evolve? Here's why head tap gesture can cause confusion among umps, players and scoreboard operators

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.

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 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.

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.

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.