Oswalt appeared to be struck in the back of the right shoulder in the fourth inning Wednesday against Tampa Bay.
The Phillies right-hander fell to the ground and remained there until a trainer reached the mound to examine him. Oswalt stood up and after a brief discussion walked to the visiting clubhouse on his own power.
Evan Longoria homered leading off the fourth against Oswalt. Ramirez, who had a RBI double in the first, was the next batter. Oswalt, making his fourth spring training appearance, struck out four while allowing three runs and four hits in three-plus innings.