"He's not going to pitch over there," said Williams. "He's not going to pitch against the Cubs."
Peavy, 28, has not pitched in a Major League game since June 8, when he was still with the Padres, as the right-hander continues to work his way back from a strained tendon in his right ankle. Following three bullpen sessions, Peavy made his first rehab start with Triple-A Charlotte on Thursday against Pawtucket and gave up one hit and one walk over three scoreless innings, striking out five.
Injury rehab start No. 2 takes place Tuesday in Durham, with Peavy set to increase his workload to 65 pitches. That workload will vary, per Peavy's final call.
"It depends how much he labors," Williams said. "If he goes back in the dugout and says, 'I want another [inning],' he's pro enough to make those decisions. He knows his body more than we do.
"Just be smart. I don't want him rushing back just because we're behind in the standings and had a bad start here or there. His health is the primary concern."
And that concern for Peavy's health is why he won't be starting during the makeup game with the Cubs, the White Sox crosstown rivals, who were in hot pursuit of Peavy this past offseason. Peavy injured his ankle running the bases and only can exacerbate the injury through running the bases.
So, when will Peavy make his triumphant return? Sunday afternoon's start for Charlotte at Gwinnett will mark Peavy's third injury rehab effort. That performance could be followed by just his third career start facing the Yankees on Aug. 28 at Yankee Stadium, during the White Sox 11-game road trip, or he could debut on Sept. 2 at the Metrodome if Peavy needs another Minor League start to get ready and stays on his current schedule.
"I know when he's pitching here," said Williams with a wry smile. "We'll see the next couple of starts, but I have a pretty good idea."
Scott Merkin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.