There is a lot of hyperbole going around about Green's contract, that simply isn't true. He is not overpaid.
Green is one of the rare NBA players who is paid exactly what he should be paid. He is really the definition of an above average NBA player. He is not a role player, he is a guy who does a little of everything, can play 36 minutes a game, give you 15/5 and solid defense at the 3 or the 4. The worst case scenario with him is that he is invisible for a while, but then he can take over games at times too. People seem to not realize that those guys don't exactly grow on trees. That is why they make 8/9/10 million a year.
While there are some teams, who are looking at cap space in the next two summers that might worry about bringing him on, the majority of teams would love to have a player like Green for $9 million a year.
Now, the C's are looking to move him, because he just doesn't really fit in with what they need right now. But I don't think there are going to be many teams that will hesitate to take on Green because of his contract.