Chicago's PK is atrocious. Its cost them a lot of close games, which is why they have played so many OT Games. Their dick PK is allowing teams to hang around in games.
Callahan for Andrew Shaw and Brandon Pirri.
Chicago could definitely use Callahan but I doubt they want to give him the contract he'll command. Kane and Toews are free agents in 2015 and they already have Seabrook, Keith, Hjalmarsson, Hossa, Sharp, Crawford, and Bickell signed long term for 4+ each. That club needs to save as much money as possible or they're going to risk losing their two best players. I really like Pirri, Shaw, Kruger, Saad, and Morin but those players are nearly untradeable for CHI because of their contracts.
The only way it would make sense to me, from a Blackhawk perspective, is if you had the Rangers take the Bickell contract back. Hossa and Sharp are too important to their team, making the Bickell contract the one expensive deal they could afford to part with. He was great in the playoffs last year but he'd be the one that needs to go to bring in Cally.
Now, from a Rangers perspective, that Bickell contract is pretty ugly. In order to take on Bickell for Callahan, the Rangers could probably command their pick of Pirri, Shaw, Kruger, or Morin. Saad is probably too good to get back.
Kruger is the guy I'd want. He doesn't get much ice time (less than 12 minutes a game) but he has more primary assists per 60 minutes than Toews. Obviously he's not nearly the player Toews is but I think he's a more than capable 2C moving forward.