Well, that certainly would be one way to use the cap space from yesterday. If Panarin really wants to come back, assuming it's not a ludicrous contract, it seems that the Hawks could make it work next year.
Columbus is in a tough spot right now. One year left on the contract before he's a UFA, it's going to be tough to convince a lot of teams to trade a lot for him when the other team knows he can walk next year. If he's got his sights set on coming back to Chicago, maybe the Hawks can take advantage.
What would it take to trade for him? Anisimov (played under Torts before, has 3 years on his contract of "cost certainty" for CBJ) plus other futures is my first thought.
Of course they could wait a year til he's UFA and trade nothing too, but then you run the risk of him being dealt to another team he's comfortable signing long-term with.