Martinez left Monday night's game against the Colorado Rockies with two outs and two batters on in the fifth inning. He was making his first start since a trip to the disabled list with a right oblique strain. He also has been on the DL this season with a lat injury.
He had been pitching a strong game before Monday's injury, striking out nine batters.
Martinez is 6-6 this season with a 3.41 ERA in 18 starts.