Hartman and/or Trenin.
Hartman is 30, has 2 years left at 4 mil, and has 10 points in 34 games.
Trenin is only 27, but he has 3 years left at 3.5 mil and only has 6 points in 34 games.
It will be tough to make this deal in-season, though. Cap space is pretty tight for Minnesota right now and they don't have much else they could move. I'd rather not retain on Mika.
Ideally, we could swap Quick at 50% (625k) for Fleury (2.5 mil) to make the cap work better, but Fleury has an NMC. The only other options would be to swap Smith at 25%, Vesey at 50%, or Carrick, for one of Gaudreau or Johansson. Johansson is a pending UFA.
Mika + Vesey@50% for Hartman + Trenin + Johansson would save them 600k overall. Swapping 3 players for 2, the extra cap space should give them enough to fill that vacated spot.
Minnesota would have to add something else to this deal, I would think, to balance the value.
It's too bad we can't trade for buyout/retained cap space. I've been saying for years that they should do this to create more flexibility in the system. If we could trade Mika for Parise + Johansson + futures, for example, that would work perfectly for both sides. They would actually gain 870k in cap space without majorly upsetting their roster, and we'd only be left with an 833k cap penalty for the next 3 years.