SEATTLE -- Mariners right fielder Michael Saunders had to leave Thursday night's 4-2 loss to the Twins when he felt a sharp pain in his side during a check swing.

The swing occurred in the eighth inning and forced to Saunders to leave in the middle of his at-bat against Twins reliever Casey Fien. The extent of the injury was not immediately known.

"He's going to get an MRI tomorrow, and we'll find out what's going on," manager Lloyd McClendon said.