Is this a keeper league? If so, how many can you keep? What does the rest of your roster look like?
If it's not a keepr league and there's something worth picking up (someone who you may consider starting at another position - i.e someone you NEED) I'd dump him. Otherwise, I'd hold him. If for nothing less, to keep him from other owners.
I'd probably ride McMichael for now, keep Heap on the bench until he's producing, and drop Wiggins if you need the roster spot. If you're only starting one TE, then it's a waste to keep three on the roster. Even two is a stretch at the TE position.