Detroit's lead was cut to one game by Minnesota, which beat Kansas City 10-7. Both teams have two games left.
The Tigers, who couldn't take advantage of an opportunity Thursday to win the division with a win over Minnesota, heard a smattering of boos during their series opener against the White Sox.
"For the last day or so, they've been disappointed," Detroit manager Jim Leyland said. "Most people when they're disappointed, they express their disappointment in the form of boos. There's nothing wrong with that."
The Tigers but got off to a bad start when Scott Podsednik hit a leadoff home run and wound up losing for the fourth time in six games.
Peavy (3-0) pitched eight scoreless innings and Carlos Quentin also homered. Out for three months because of an injured right ankle, Peavy gave up just two hits and showed the form he had as the 2007 NL Cy Young winner.
"I still don't feel 100 percent," Peavy insisted.
Edwin Jackson (13-9) gave up a career-high eight runs and seven hits over five-plus innings.
"The one thing you have to have when you pitch against a guy like Peavy, your pitcher has to pitch good," Leyland said. "(Jackson) just made way too many bad pitches in the middle of the plate."
If the Tigers fail to hold off Minnesota, they will become the first team in major league history to lead a division on May 10 and stay atop it until losing the title in the last week of a season.
Detroit still has an opportunity, though, to win the AL Central without any help from the last-place Royals. With a magic number of two, the Tigers can wrap up the division by beating the White Sox the next two days.
"We're just trying to win theses games," White Sox catcher A.J. Pierzynski said. "We don't have a vendetta or anything because it's Detroit or Minnesota."
The Tigers are set to start Alfredo Figaro (2-1) on Saturday night against Freddy Garcia (2-4) and the White Sox.
"I know it's an important game," the 25-year-old Figaro said quietly on the eve of the third start in his career. "I'm not nervous. I'm a little bit excited."
If the Tigers need to win Sunday to clinch the division, they plan to put Justin Verlander (18-9) on the mound against John Danks (13-10).