At this point, it doesn't seem likely that this trade means anything about a possible deal for Peavy, especially if the Padres continue to ask for the moon in a deal. It does probably mean that if this trade is real and does happen, one would have to imagine that this is a precursor to the Cubs signing their RF for next season, being it Milton Bradley or Adam Dunn.
But could the Cubs be ready to jump back in on Peavy? Moving Marquis does save some money that the Cubs would need to help pay Peavy, and a rotation spot. But with Sean Marshall on the team still and Rich Hill being out of options, the Cubs are still set at the 5th starter spot. There wouldn't be a noticeable drop off from Marquis to Marshall, and they would still have one of the top rotations in baseball. But Peavy gives it that little bit extra.