In a bizarre scene, Perez was left standing around in his socks during a delay in the fifth inning, waiting for someone to bring him new shoes before he started his outing against the Boston Red Sox.
Perez was warming up when he noticed that something was off with his left cleat. He called for time, then signaled for a fresh pair of Nikes.
While a trainer fetched them from the clubhouse, the 37-year-old Perez meandered around the mound in his socks. He stepped onto the grass to lace up the replacement footwear, then finally got to work.
He said after the game that the toe spike came loose when he was grooming the mound getting ready for the first batter he faced.
"It never happened to me before,'' he said. "It's kind of funny. It's part of the game.''
Boston socked it to him after that. Jackie Bradley Jr. hit an RBI double to make it 6-3 after Perez retired the first batter, and Leon followed with his drive into the Green Monster seats.
"I heard he busted out of 'em,'' said Bradley, who was on-deck. "I've never seen anything like that. I didn't actually see it, still. I was still trying to do my homework on him.''
The Red Sox won the game 12-5.
The Associated Press contributed to this report.