How he commands the huddle, team. Taking note of how his teammates and the coaches behave around him, and what happens when certain situations of adversity arise in-game. A crisp and clean variety of throws showing off his arm and hitting on the necessary routes, with touch and zip.
Seeing if he's improved upon his timing, and watching his footwork in the pocket (which I believe are quite good). I guess what it boils down to for me are: leadership, getting close to 8 wins, and how he handles pressure and adversity.
Nothing set in stone or a narrow threshold, just some of the general nuances that this team has been lacking at the QB position for so long. I'm believer that you can 'see and feel' it once you've seen over the course of games and bullets flying.
Quite honestly though, I think it will be a difficult assessment no matter what he does, in terms of having such a small window of perceived opportunity and scrutiny - of course that said, barring a miraculous playoff run (which is highly unlikely).
