I don't think they will trade from the bull pen because Wick comes back. I think they will trade from the bullpen because they should be able to get some pretty good prospects without pulling the trigger on giving up on the season.
At least that is what I hope they do. As you say, hot groups, especially bullpens, can turn around in a hurry. In a season where the prevailing opinion is that the Cubs are not a top tier club, trade them while they are hot.