"Phillies starter Cole Hamels underwent a precautionary MRI Monday on his pitching shoulder, a source told CSN's Leslie Gudel.

After Hamels' last start, in which he lasted only five innings in a loss Friday to Washington, manager Charlie Manuel said Hamels felt stiffness in his shoulder.

The left-hander chalked it up to a dead-arm start, which happens over the course of a long season.

"It was just one of those things where I wasn't able to get loosened up," Hamels said after the game. "It's that time of the year where you're a little fatigued a little bit and battle through it and move on to the next game.""