The surgery will be done by Dr. Anthony A. Romeo at Rush University Medical Center -- but this is not a case where he is only having the surgery in Chicago out of convenience.
Peavy consulted with famed surgeon Dr. James Andrews along with a host of other doctors, all of whom pointed to Romeo.
"What's amazing is I spoke to a couple of doctors this morning," Peavy said. "Their overwhelming choice was Dr. Romeo in Chicago, without knowledge of [the fact that he was scheduled to do it]."
The injury is a very rare injury, in which the muscle ripped completely off the underside of his shoulder that it is usually connected to and now resides somewhere below his shoulder blade. The latissimus dorsi is partially responsible for the internal rotation of the shoulder joint.
Peavy said that for most people the injury would not have occurred, but the violent overhead motion of the arm is what caused the muscle to snap clean off its moorings. The muscle does very little to inhibit his everyday motions.
Doctors feel that he should be able to regain his full velocity back from before the injury, but it remains speculation because there aren't very many precedents for this type of injury.
"Nobody's had the surgery in baseball that we know of," Peavy said. "This has happened in baseball, but not completely detached. So I guess I'm a guinea pig and see how it turns out."
Part of the reason Romeo was recommended is because he is one of the only doctors who has conducted a surgery that is very similar to the one at hand.
As for his recovery time, Peavy believes he will be fully recovered by Spring Training of next season, but, again, there are not many precedents for this type of injury.
"We hope to be up and throwing by Spring Training," Peavy said. "Obviously, this is uncharted territory because it's not common. While [pitchers] have torn lats, they've never completely torn off the bone with no attachments left. And that's where we're at. We're hoping, around the start of the season, to be back in action."
Peavy will be staying with the Sox, after the surgery, in hopes that he can provide moral support as they go through an expected pennant race.
"I'm not going to leave the team," Peavy said. "I love being part of the team. [Team trainer] Herm [Schneider] and the guys are going to do my rehab. To be a cheerleader for the rest of the season, obviously that's a tough pill to swallow, but it's exciting that the boys are playing as well as they are and I was excited to be a part of it while I could and see things turn around."
When he reflected on the injury, he feels that if given the same options, he would have done the same thing, despite fighting fluid in that shoulder about two weeks before the injury.
"Hindsight is 20-20 of course," Peavy said. "I've never been hurt [like this], so it's hard to say that what you're feeling would lead to something tragic like this happening. If I would have known, then obviously I would have backed off it. It was just a grabbing sensation, nothing really sharp. It got sharp in a hurry."
Louie Horvath is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.