The Blackhawks have some trade assets, but the player that fits Detroit's immediate needs is Ryan Donato. While there is still a chance Chicago gets him re-signed, it becomes clearer with every passing day that the team won't be able to. There's no logical reason to keep Donato without a contract through the trade deadline.
That being said, the Blackhawks should be seeing if there's interest in Donato by the Red Wings now. Copp and Donato are different players, but that's okay if Donato can still do a job and continue playing similarly to how he has this season with the Blackhawks.
Donato wouldn't have the same role in Detroit and I believe both teams know that, so that may limit the return to Chicago. It was initially believed that he would go for a third round pick, and while the 28-year-old has played very well this season, I think that's still the asking price.