I loved Andrei Kostitsyn as a prospect, I thought he was going to become something good. He has some good years with the Habs early in his career when he looked like he would become a star player, but his play just seemed to lack passion as he gained more experience and stopped developing.
I was surprised when he left for KHL because I thought he might be able to thrive in a different environment after being stuck in the fish bowl in Montreal for so long, but I think he might have been "blacklisted" around the league after his evening out with Alexander Radulov. His play seemed to pick up right away in his brief stint in Nashville (12 points in 19 RS games, and 3 goals in 8 playoff games).
You never know what injuries might crop up in TC/Preseason. And Andrei is thickly built for an offensive player (like Kovalchuk) and can play physical as well. If the PTO happens and he plays up to what he's capable of in pre-season, I'd be all for adding him.