Corpas, who relieved starter Esmil Rogers with two outs in the second inning, gave up a double to Brian McCann leading off the fourth and then stepped off the rubber and motioned toward the Rockies dugout seeking the team trainer's assistance.
After a brief examination and consultation on the mound, Corpas walked off the field holding his right elbow. Reliever Matt Reynolds replaced him.
Colorado manager Jim Tracy said Corpas was scheduled for an MRI scan on Thursday.
Corpas went 1 1/3 innings and allowed three runs on four hits, including Omar Infante's home run in the third inning.
Information from The Associated Press contributed to this story.