Rays closer Troy Percival could be headed to the disabled list after falling down on the mound and leaving Wednesday's game as a result of tightness in his troublesome left hamstring.
Percival left the stadium immediately after the game to get an MRI, though the Rays don't plan to make any announcement until Thursday.
"We're just keeping our fingers crossed,'' reliever Dan Wheeler said. "He seemed in good spirits and he doesn't think it's too bad. Hopefully we'll be able to hold the fort down while he's gone and make sure we continue this winning baseball. He's a big part of what we've done.''
At the least, Percival seems likely to be sidelined a few days, so it would not be a surprise to see RHP Grant Balfour, who has been pitching extremely well at Triple-A Durham (1-0, 8 saves, 0.38 ERA, 1 run in 23 2/3 innings) in the clubhouse Thursday. (The Rays could send down INF Ben Zobrist to make room, then just wait a few extra days before activating INF Willy Aybar from the DL.)
Percival was one out from his 15th save when he fell on the mound after delivering a third strike to Brandon Boggs for the second out of the ninth inning, his eighth pitch of the inning. He tried throwing a warmup pitch to test the hamstring, but shook his head and walked directly to the clubhouse. Percival had tightness in his hamstring during a game in Oakland last week.
"Same spot, same thing, it just tightened up on him,'' manager Joe Maddon said.

[James Borchuck, Times]