Zambrano's trade value was at its absolute lowest last summer. He came back in the second half and pitched really well, thus improving his trade value. But it's still pretty low. Why not hold on to him through the first part of the season? He should be able to put up good numbers again, possibly really good numbers, because he has for most of his career. That will increase his trade value, and assuming the Cubs are out of contention, they stand to get a much better return by waiting until June/July. No reason to jump on this trade idea too soon unless the offer is really, really good!