Interesting question. He can't feel good about how he is being used, or how he has performed in Buffalo.
He is due $2.2 mil in base salary, plus $1.8 mil option bonus if he stays with the Bills. Will another team think enough of him to top that is the question.
If another team makes him a good offer I think he takes it. If there is no such offer, he stays with the Bills for the $4 mil and tries to put a resume together next season for when he hits the UFA market that Spring.
EDIT: I chose option 3, that he will not opt out. Mainly because based on his body of work to date, I don't think any other team will make him a big $$$ offer.