I live in Lyon and I've seen him play 3 or 4 times since the beginning of the season. I can say that he is still a bit lost on offense, tried to use pick and roll with TP9 but didn't work well. When he's on he's a very athletic center and can make some damage on offense, especially in the french league. Defensively, he's still a really nice defensive player and can run the floor a little bit. He was coming of the bench when Turiaf has been playing here, but he has stepped up since the NBAers left.
I'm not sure he would leave ASVEL, he's a crucial piece to the team this year, I think he's trying to play a full year here before trying a comeback in the US. He could be a nice 3rd option at center for the C's, but I'm sure Ainge can find somebody else more available than him (Elson ?)