Possible but seems unlikely. I don't think Shanahan wants to start again with a new QB especially with an aging team that probably has to win in the next couple years.

If they can't get a deal done more likely they make him play out his final year and then franchise tag him while they search for his replacement but I think a deal will get done. It suits both parties. 49ers need stability at QB for the next few years (and hopefully longer) and Purdy needs to hit the big pay day in case he turns into a pumpkin. I don't think he will turn into a pumpkin but two elbow injuries now and he wasn't as good this year.

For me, as long as the early year cap hits are low so they can keep a great team around him and as long they have decent outs after 3 or 4 years so if he does turn into a pumpkin they aren't tied to him for 7 or 8, then AAV doesn't really matter. It will get headlines and people will say he isn't worth that much but the structure of the contract is much more important to the team.