Who would I give up? probably more than most. I would offer then their choice of Wallner/Larnach/AK, Gonzalez, and a young pitcher in someplace in the 30ish ranking. But before doing that I would look to see if anybody has any interest in Santana and take whatever was offered, look to trade Farmer again for whatever somebody is willing to offer. I bring up Lee to take Farmers position. Would the Twins do what I suggested, nope, would the Twins do anything to get Vlad, mostly likely not.
Doing what I suggested cleans up the 40 man a bit, gets rid of one of the lefties that might hold Jenkins or Erod back, gives the team a chance to get Lee acquainted to the majors by setting him up with good matchups, and could get reduce "some" of the payroll that Santana and Farmer are taking up (I assume the Twins would more than likely have to cover some of their salary. And possibly might take some pressure off of Lewis by having another guy to help carry the load.
IMO going into to next year every outfielder on the 40 man has fairly big question marks (Buxton injury, Kepler FA) if they can reduce some of those question marks and open spots up for others all the better.