I think he's more of an off-season move, you'll have teams striking out on signing their own versions of Rakell in free agency and would circle back to him to trade for him. He's in a similar position to Rust, in that he'd likely be getting a similar if not larger deal than what he has left if he hit free agency this off-season.
If he's traded now, I think it would probably be a multi-year contract plus a 2nd or something like that in value. It wouldn't work because Arvidsson is hurt, but I wonder if Edmonton would pull the trigger on Arvidsson and a 2nd for Rakell. That deal both gets out of a contract of a guy that's not working there while also giving them an upgrade (at least current upgrade, I think the two are fairly similar normally).