I doubt he's "cooked", he was productive last season, and takes great care of himself. A consummate over achiever, and I mean that as a supreme compliment. I was highly skeptical that he would make it in the NBA, and man he proved me wrong.
As someone else mentioned, he would be great instant offense off the bench, and mentor for Nesmith, who really can model his working 3 point line off of him. Mike Schmidt as I recall in his video session with Nesmith pointed out footage of JJ to Aaron as a guy he should work to emulate.
But no 1st round pick, unless highly protected, and even then I'd really hesitate.