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04/19/11 7:00 PM ET

Peavy's prognosis better than initially feared

ST. PETERSBURG -- The latest injury update on Jake Peavy wasn't nearly as bad as imagined when the right-hander exited Monday night's Minor League rehab start for Double-A Birmingham after just 15 pitches.

Whether it's a short setback or more of a long-term derailment remains to be seen, as Peavy's recovery process from experimental surgery on July 14, 2010, to reattach the tendon that anchors the latissimus dorsi muscle to the rear of the shoulder hits another bump on the comeback trail.

According to the White Sox, Peavy left Monday's game with muscle tenderness (irritation) in his right posterior shoulder (the lat area). On Tuesday, the White Sox flew Peavy to Chicago, where he saw team doctors and had an MRI.

Everything was normal, with no signs of any problems, according to the MRI. That test was followed by a clinical exam, also proving to be very benign.

The latest plan is to start Peavy on a six-day course of anti-inflammatory medication. During the first three days, Peavy will solely take the medication and won't do any throwing. On the fourth day, he's going to resume a throwing program.

If this plan works as laid out, Peavy would miss Saturday's Minor League rehab start with Triple-A Charlotte. He would then go back on a regular schedule with bullpens and side sessions to prepare for his next start, which originally was scheduled for Thursday, April 28.

Monday's pitch count was set for 90 pitches and Saturday's pitch count was to top 100, getting Peavy ready for a possible Major League return during the last weekend of April at home against Baltimore. His early exit probably indicates Peavy will need another two starts, meaning a May 8 start in Seattle could be the next return target.

Of course, that return is written in pencil and ready to be erased and changed as needed. For the currently active White Sox, it's a mix of good thoughts for Peavy but more of a focus on the players who are fighting the Rays in St. Petersburg.

"You wish the best for [Peavy]," said White Sox reliever Matt Thornton. "I heard about last night, and you really feel for him when a guy is going through injury troubles and has another setback.

"He's making progress and has another setback, but that's OK as long as he's here for the longer haul. Hopefully, he gets here sometime in the next few weeks or month and helps us through the summer and postseason. We care about him, but right now, it doesn't affect our team up here."

Barring any personnel moves made by White Sox general manager Ken Williams, Phil Humber continues to hold down the rotation's No. 5 slot in Peavy's absence, and Jeff Gray stays as the seventh reliever and 12th pitcher on the staff. Humber will start Wednesday against the Rays at Tropicana Field.

Peavy threw a 34-pitch bullpen this past weekend in Chicago and then expressed confidence to the media concerning his positive direction taken toward Chicago. This latest rehab run, covering three starts, including the three runs on four hits scored in two-thirds of an inning on Monday, was the culmination of working his way back from rotator cuff tendinitis. That bout of soreness shut him down after a Spring Training start on March 19 against the A's.

While this latest problem is disappointing for all involved looking at the finish line, there's still no sense Peavy's ultimate goal for return has been jeopardized.

"What I'll say about that is he had major surgery," White Sox pitching coach Don Cooper said. "It's something mentally that's going to be on a pitcher's mind. He's got to have thoughts like: 'Am I going to get well. Am I going be the same guy that I want to be?'

"From what we saw in Spring Training and how he threw the ball, going by gun readings and everything, it was very, very similar to what we had last year from him. To me, it's like climbing a ladder. Once you get to top of ladder, you are healthy. Then you try to build up strength from there. We're not there yet."

White Sox manager Ozzie Guillen will worry more about Peavy once he actually joins the team.

"I just let him go through the process because you don't know exactly what we have," Guillen said. "What they told me was good news. Now they have a plan for him, between Coop and [White Sox head athletic trainer] Herm [Schneider], about what's the next time he's going to pitch. I was kind of worried last night, but with the news we have, I feel better.

"In the meanwhile, I stay with the same plan. I wish I can say I will have this guy the next day, one week, two weeks, one month. I've got to wait and go through the process and see what happens."

Scott Merkin is a reporter for MLB.com. Read his blog, Being Ozzie Guillen, and follow him on Twitter @scottmerkin. This story was not subject to the approval of Major League Baseball or its clubs.