Jake Peavy has possible setback

GLENDALE, Ariz. -- The positive momentum surrounding Jake Peavy's recovery from surgery hit a snag Sunday as the Chicago White Sox shut down the right-handed pitcher with what is believed to be rotator cuff tendinitis.

Not only is Peavy out for his next spring start, Thursday against the Cubs, manager Ozzie Guillen is also saying the right-hander likely will miss the start of the season, which means a stint on the 15-day disabled list could be forthcoming.

On top of all that, Guillen appears to have lost his trust in Peavy. The right-hander convinced the White Sox last season that he could pitch through pain and he blew out his latissimus dorsi muscle. This spring he told them he was capable of pitching through soreness and then came Sunday's setback.

"Believe me as long as I am the manager of this ballclub that is the last time he convinces me," Guillen said after Sunday's 9-7 defeat to the Dodgers. "I will make the call. I will have the power to let him go out or not. I know it sounds powerful but the last two times he didn't convince me, he convinced everybody he could go out there and perform and the next day we get bad news.

"I am the manager of [this] club and I was the guy who was against [him pitching Saturday], but he said he was fine and ready to pitch. I have full responsibility of players and at end of the day it's on my shoulders how people get hurt or not."

Peavy, who is on anti-inflammatories, will be reassessed Monday.

"I know they said the first 48 [hours] will be a telling tale," Peavy said. "It's a day-by-day kind of deal. We've been going full-steam ahead since we started this thing and we were told [to] expect this. I wouldn't buy into it and I never expected it. I'm not going to sit here and call it a setback because we don't know what it is yet. But certainly things have slowed down."

Guillen was optimistic Peavy would start the season with the White Sox after he threw 83 pitches Saturday. It was his longest outing of spring training as he continues to rehab from surgery last summer to reattach his latissimus dorsi muscle.

Peavy has admitted to shoulder soreness for most of the spring, but tried to blow it off as the typical discomfort associated with trying to get his arm in shape for the season. Clearly it was something more.

Peavy has made four starts this spring: March 4 against the Angels, March 9 against the Giants, Monday against the Padres and Saturday against the A's.

"Obviously you have soreness and different stuff pop up, but this is something that I kind of felt a tad after the [Angels] start and felt it a little more after throwing [against the Giants]," Peavy said. "It's just been creeping up and reared its head in the last week. Today I didn't do so well in tests they wanted to put me through. It caused them to go, 'You know what, let's pull back a little bit and make sure ...'

"I can tell you this: When I get back to Chicago and on this team I will be ready to go as much as I can be. There will not be anything ailing me out on the field. I will be as good as I can possibly be. The decision was made today to slow things down to nip things in the bud."

While set to take a stand against Peavy's determination, Guillen did say that he isn't mad at his pitcher for trying to be a hero.

"I respect him because he wants to be out there," Guillen said. "I love when players want to be on the field. That's the best thing that can happen to any manager. In the meanwhile, he's a different dog. He wants to be out there fighting. He's that type of guy who has the [temperament] and passion for the game. He wants to help. Sometimes when you want to help, you don't really help."

Not only has Peavy been rehabbing from surgery, he's also been battling a stomach virus that kept him bedridden for two days last week. Despite it all, he continues to put a positive spin on things.

"Once you start going close to game speed and then game speed like I have, things can pop up," Peavy said. "You're asking your body to do exactly what you're going to do in the regular season. It obviously has caused a little bit of discomfort. It's a small step back and we'll re-evaluate the situation in the next couple of days to see where we go from there."

Philip Humber will start Thursday's game against the Cubs. If he fares well he could be lined up to take the fifth spot in the rotation, which could be pushed back to April 10 because of an off day early in the season.

Doug Padilla covers the White Sox for ESPNChicago.com and ESPN 1000.