Melky has been pretty solid all year. Reynolds has been doing well recently, but still sports an iffy average. Swisher has been getting better. Smoak has been pretty good, minus the power department. And, Damon has just been doing it all for the Rays.
Of them, I would probably add Damon if you need runs or OBP (he had a 39 game on base streak to start the season), Smoak if you need AVG, Reynolds if you need power (and a couple SBs), Swisher for RBIs, or Melky for all around.
Every one of them has a decent reason to be used. So, look at the cats you're weak in and pick one to compensate.
Good luck! (Yes I left two out. I haven't followed them much or at all this year.