keep opposing defenses honest, or carry the offense when the passing game isn't working. That's going to have a noticeable impact.
Now for the record I think Tanner is going to have a great season if he can stay healthy; with that extra game and the weak second half of the schedule 4,000 yards passing is a possibility. But if he gets injured, especially during the tough games in September, then it could be a long, long season.