Soon after reliever Kevin Kelly started warming up in the bullpen, Tampa Bay manager Kevin Cash and a trainer went to the mound with two outs in the fourth and the game tied at 2. After a discussion, McClanahan left the field.
Cash said there were no plans for additional tests.
"I don't want to speculate, it's still pretty early, but the leading notion is we don't think it's anything severe," McClanahan said, "Just maybe more of a precautionary move just to maybe limit whatever it is."
The left-hander (11-1) was looking to become the first 12-game winner of the season. He allowed two runs, four hits and walked two during a 66-pitch outing.
"It was something he felt before his last start and he kind of managed it really well," Cash said. "The way the ball was coming out (tonight) I think we was favoring it a little bit more. In those moments we need to err on the side of caution."