PITTSBURGH -- Pirates right-hander Jeff Karstens underwent an MRI on his right groin on Friday, the results of which indicated that the pitcher's hip flexor was the source of the discomfort.
Karstens was removed in the fifth inning after feeling tightness in his right groin while rehabbing his right shoulder at Triple-A Indianapolis on Thursday.
Turns out it was good news for Karstens, who dealt with a groin injury in 2008 and did not want to repeat the experience. "Right now, it's day to day. It feels a lot better today than it did yesterday," Karstens said. "I didn't really want to take it any farther, because I didn't want to aggravate it any more." Karstens was also relieved that the injury didn't come to his already injured shoulder. He hasn't appeared in a Major League game since April 17, when he pitched an inning against Arizona. Karstens was placed on the 15-day disabled list on April 18. "It's extremely frustrating, because I've been working so hard to get back," Karstens said. "This was supposed to be my last outing. "[The shoulder] feels great. I haven't had any -- knock on wood -- any setbacks with my shoulder. So, that was definitely a positive for me."