I don't see it possible outside of him being an expensive rental. We'd have to pay a premium to Toronto to unload Richards if we have hopes of re-signing Sekera should we acquire him.
I don't think Voynov is done, though I am hesitant to see what kind of hockey player we get back after the ordeal he's gone through. We don't have much information available, but I'd be surprised if he is found guilty and receives any punishment that would take him away from the team for any extended period of time.
If we get Sekera, I see him as a pure rental, and if I were Dean I would hold off; however, if we were going to make the deal, I think others are correct that Weal and a 2nd would be a good price to pay.