CHICAGO -- The upbeat and exceedingly positive Jake Peavy, on an almost hourly display since his return to the White Sox on May 11, was understandably absent following Sunday's 7-3 loss to Detroit.

The noticeably dejected version of the intense right-handed hurler didn't come about specifically from the White Sox losing this weekend series to a team they are chasing in the American League Central. His feeling wasn't even directly tied to giving up six runs in four innings and suffering his first loss of the 2011 season.

Instead, Peavy looked a bit beat up after having to deal with yet another injury.

Peavy exited Sunday's setback following just four innings and 75 pitches, leaving with a strained right groin. The injury will be re-evaluated on Monday, but Peavy's postgame tone and comments made it seem as if he is likely to miss at least his next start.

It's a tough situation to deal with after Peavy fought so hard to come back ahead of schedule from surgery to repair a torn lat muscle from last July.

"To battle back from what we battled back from ...," said a subdued Peavy, while standing in front of his locker. "It'd be one thing if that was bothering me.

"But for something like your legs that keep you from making your start, it's frustrating. I'm sorry. I don't even know what to say."

There didn't appear to be any injury problem for Peavy through the first three innings, when he retired all nine Detroit hitters on just 38 pitches and struck out four. He actually started feeling it grab in the second, enough of a grab to have him come down after the inning to get a wrap on it in the clubhouse.

When he broke in the fourth to cover Don Kelly's ground ball to first baseman Paul Konerko, a potential game-changing double-play grounder that wasn't turned by shortstop Alexei Ramirez, he felt the pain really flare.

"After that, it was hard for me to stay mechanically anywhere close to what I was previously," said Peavy, who gave up six runs on three hits and three walks in the fourth, using 37 pitches for the one frame that was topped off by Ryan Raburn's grand slam.

"Right now, we're going to evaluate him," said White Sox manager Ozzie Guillen. "They're going to evaluate him and see how bad he is. He was feeling that since Boston, the last time he pitched. All of the sudden, it started bothering him again after that inning."

An illustration was provided by Peavy of how the injury affected his mechanics in the fourth. During a 13-pitch at-bat against Miguel Cabrera, resulting in a walk, Peavy was trying to go away from the Detroit slugger and almost hit him up and in on a couple of pitches.

"You watch where my pitches went: They went where they were intended to go the first three innings," Peavy said. "I think I walked one guy all year and I walked three guys in that inning just trying to piece it together."

While acknowledging the amazing technology and equipment used to treat injuries, Peavy added that he can feel the groin soreness when he walks. He couldn't imagine "in four days or five days from now it being completely gone, when I can go out and drive off a mound and pitch in a game."

Guillen's crew has been working with a six-man rotation since Peavy returned. They would have five quality starters already in place, even without the veteran right-hander.

Nothing is etched in stone, at this point. So, Peavy has to see how his body responds, something he has been doing far too much to his liking over the past three seasons.

"I had it today," Peavy said. "Today could have been a special day, a fun day to be out there, a good day for us to win a series. Right now, I'm as frustrated as you could imagine."