The pirates so far have not have had the difficult choice of choices who will be the 5 starts in their rotation. The bottom 3 are Charlie Morton, Jeff Karstens, and Kevin Correia. Once all three are healthy a though choice will be made. One of them will have to be put in the bullpen, sent to the minors, or traded. We already have a long reliever in the pen in Brad Lincoln, so that is not the best possibility. I don't think sending them to the minors will help them improve any either.
So it comes down to a trade. The most likely to be traded is Kevin Correia, because he is under contract for this season only and has not preformed as well as he did last season. Even thou he was an All-Star last season, there would be a very small trade market for him. To the right trade partner we would be able to get a good left handed relieve, or maybe a good power bat off of the bench. The pirates need another power bat very badly, but Hurdle like to have a couple leftys in the Bullpen. Once all three are healthy, I think that this is the most likely option.
The pirates could also trade Morton or Karstens. There may be more trade value with them, but by trading them would hurt the team long term. I think they can still develope into quality starters and will be a valuable asset to the team going forward.