At least one Seattle Mariners player was blatantly stealing signs during Game 4 of the American League Division Series on Wednesday.
Mariners first baseman Josh Naylor appeared to have picked up a tell from Detroit Tigers pitcher Casey Mize during Wednesday’s game at Comerica Park in Detroit, Mi. Naylor could be seen aggressively signaling toward Mariners hitters while on second base.
Mize was certainly aware of what was going on, judging by his reaction to Naylor.
Looks like Josh Naylor had a tell on Casey Mize’s splitter from second base — and Mize appeared to notice, glaring at him after his K to Eugenio Suárez.
— Daniel Kramer (@DKramer_) October 8, 2025
Then just before Dominic Canzone’s double off the splitter, Naylor lifted his left arm seemingly as a signal. pic.twitter.com/7JV1SWx63p
Naylor seemingly lifted his left arm every time the splitter was coming. Perhaps it was not coincidental that DH Dominic Canzone was right on one and singled Naylor in from second to give Seattle a 1-0 lead.
Naylor kept it up when he reached second base again during the fourth inning. He could be seen waving both arms at times while pitcher Tyler Holton was in the set position, seemingly trying to relay the intended location of the pitch. The Tigers were aware of this, as catcher Dillon Dingler seemingly set up inside on an 0-2 pitch to Mitch Garver, only to move outside as the pitch was about to be delivered.
"I don't like it."
— Jomboy Media (@JomboyMedia) October 8, 2025
Adam Wainwright was in the broadcast booth mind blown by Josh Naylor blatantly relaying signs to the batter from second base https://t.co/8eJkbhStox pic.twitter.com/3R5eS1t5BD
Broadcasters AJ Pierzynski and Adam Wainwright were shocked by this. The sign-stealing did not confuse them, but they were both surprised by how blatant Naylor was being.
“This is blatant,” Wainwright said at one point, suggesting the Tigers needed to do more to throw him off.
Holton walked Garver after getting ahead of him 0-2, so it’s possible Naylor was causing some serious distractions. Despite that, Seattle only got one run out of the situation despite having the bases loaded and nobody out.
Naylor and the Mariners were not doing anything illegal, as stealing signs is only a problem is teams used some sort of organized, technology-based method of doing it. There was no evidence that was the case here, but it’s certainly going to annoy the opposition despite its legality.
Most teams look for tells and give signals when they can get away with it, as the New York Yankees did to the Toronto Blue Jays earlier this season. Generally, it falls on the pitcher and catcher to figure out what they’re giving away and how to stop it.
Naylor’s moves helped the Mariners early, but not enough to close out the series. The Tigers came back to win 9-3, forcing the ALDS back to Seattle for a decisive Game 5 on Friday.
