I'm confused as to why he isn't staying on the shelf. Peavy wasn't exactly dominant in his Triple AAA stint, going 1-1 in four starts, with an ERA just barely below 3.00. Peavy isn't expecting to be great: “I don’t expect to be 100 percent. I’m not."
Chicago isn't a team looking for a veteran at 75% or 80% to get them a win--they are six games out, in 3rd place in their division. They have no shot at the Wild Card (obviously--no team in the Central does--Division leader Tigers would be 8 games out of the Wild Card if they weren't in first). So maybe that's the logic of the White Sox--"Our Division Sucks, and with a guy like Jake Peavy, we believe there's no reason we can't make up that six game ground on the Tigers."
But...The White Sox record in the division is 27-30, and they've got 15 of their remaining 17 games against teams in that very Central Division. Of those 15 games, only 3 are against the total bottom feeders of the Central, the Cleveland Indians. You may not think much of the Royals, but they are 7-3 in their last 10 games, and they can beat any team any time. For example, they destroyed Detroit tonight, 11-1.
My overly set-up point is this--there is nothing in the team stats, nothing in Peavy's stats to suggest that the White Sox can make a run with him this late in the year. Peavy isn't 100%--he says so himself. So why put him out there? They've got Peavy locked up for a half-decade. They gave up four minor leaguers to get him. Do they really think that Peavy is going to come in and generate so much interest that they can trade him again and break even? Because they can't. Do they think their campaign this year isn't done? Because it is. Do they think Peavy will be helped next year by getting a few starts this year? Because I don't see how.
In short, I don't see how or why this decision gets made. Put your injury-prone veteran pitcher on the shelf, you stupid White Sox. There is absolutely no benefit to starting him this late into the year, when the rest of your team is as sketchy as it is.