I'm dragging this over from the general trade rumors thread.
I don't think Johnson and Peavy is nearly enough. Piscotty is rated the number 49 prospect in their mid season top 50, and BP has him at 30. No matter how you look at it, he's a top 50 guy and you aren't getting that for a veteran rental who is, at best, a middle of the rotation guy for the Cardinals and a low ceiling high floor prospect like Johnson. If you want that kind of return, you have to give up some real prospect value, and Barnes has first round pedigree. He's also a bit broken right now, so he seems like the most obvious fit from the back end of the top tier pitching prospects the Sox have to be sent out.
At this point, with the 2014 season swirling down the drain, I'd rather hold on to guys like Webster, Ranaudo and DLR, save for an opportunity to grab a young offensive monster like Stanton.