It doesn't necessarily have to be a bidding war, but I think teams will make him offers. If he's a full free agent with no strings, a handful of teams will throw some kind of offer at him. And that means he has options.
His best course of action would probably be to sign a deal to get through this season and show that he can still play - to set up his ability to sign something more meaningful in the spring. The best way to do that is to sign with a team that gives him a chance to put up some production.