I read this on Yahoo... "got some good news. He didn't tear the groin muscle that forced him out of Wednesday' start, but instead has a tear in the sheath surrounding the muscle. When Oswalt throws, the muscle protrudes through the sheath and gets pinched, causing pain. There's still a chance he may have to go on the disabled list, but it's also possible he only may have to miss his next start. If the problem persists, it would be corrected by offseason surgery."