This reads more like GM/agent droppings to me than reality. Heyman tosses the Brewers in offhandedly (despite their mention in the headline that was likely written by someone else). Peavy to the Brewers always seemed like a relatively bad idea to me given his contract and what I thought we'd have to give up to get him. The apparent terms of the White Sox deal, however, made me think we wouldn't have to give up nearly as much as it once appeared.
With the White Sox, and maybe the entire AL, now off the table, It seems likely to me that the Brewers were dropped as a possibility by the Padres in the hopes of pushing up the price the Cubs might be willing to pay to get him. If so, I don't really doubt that Peavy's agent would play along with the rumor if Peavy's resigned to being dealt sooner or later and he'd really prefer to play for the Cubs as opposed to anyone else. Obviously we know that Melvin was talking to the Padres last week. While I'm skeptical that Melvin is seriously pursuing Peavy, he probably doesn't mind being used to drive up the price the Cubs might eventually pay to finalize the trade.