"I've seen guys slide on the bat on a play at home plate," manager Joe Girardi said, "but I've never seen anyone step on the bat."
"You're almost happy that's the case," Derek Jeter said. "I thought he had pulled a hamstring."
The injury comes at an inopportune time for the Yankees, who were short in the outfield to begin with. Thames is the third New York outfielder to suffer an injury this month, with Curtis Granderson on the disabled list with a left groin strain and Nick Swisher missing the past four games with a left biceps strain. Like Thames, Swisher is listed as day-to-day
Thames' injury forced Girardi to play Pena in right field for just the second time in the utility man's career -- with the first time coming last Sunday. Girardi wasn't sure if the Yankees would call up an additional outfielder for Thursday's game with Tampa Bay. The situation is complicated by the injury to Jorge Posada -- who is out three to four weeks with a hairline fracture in his right foot -- and the uncertainty surrounding Swisher's return. The Yankees sent down outfielder Greg Golson earlier this week to add an extra relief pitcher.
"There could be a couple moves tomorrow," Girardi said.
Thames is batting .357 on the season, with two home runs and 10 RBIs.
Tim Britton is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.