That's not necessarily true. If he doesn't sign extension, and they have a and year, he is gone for nothing. At this point, having to rebuild, draft picks and short term contracts are nice so you increase your own chance of tanking for a good pick and have cap flexibility to replace him. Which is a heck of a lot better than nothing. Any team getting him is going to want assurance he will resign, so he can decide where he gets traded too unless the team wants to gamble without knowing they can retain him, which I doubt anyone would give up good assets for.