The team described the injury as a detached latissimus dorsi muscle in his right posterior shoulder.
Peavy said the injury was so rare that he would visit or consult with two of the leading orthopedic surgeons in the country, Dr. James Andrew and Dr. Lewis Yocum, to figure out what will be his next step.
"Obviously surgery looks the way that we probably have to go and if that is it, we'll just ride it, you know," Peavy said.
"We're going to go the best road, whatever the doctors think feels best for me and my career. We're going to do it and obviously I'm going to bust it in rehab and do all I can to be back and be back feeling better and healthier than I am."
That's likely not going to be this season.