I love preseason because you get to evaluate players in simple schemes. You see players doing basic things. It shows whether they understand the concepts or not.
Does the Linebacker key on the offensive line, read pass and drop at a 45 degree angle with his head on a swivel, looking from his number ones to number twos?
Does the defensive back have a smooth backpedal, does he backpedal until the last second when he has to turn on a post pattern and then defend with his inside arm?
Does the safety take the bait of a tight end in deep coverage, or does he play the deepest man on the field like he should?
Does the running back understand where the hole should be and when it should open? Does he take counter steps, and look sharp, or just give a token fake?
Does the linebacker or defensive end chuck the tight end in an obvious passing situation, or get greedy and let him go in order to rush the passer?
Does the linebacker have the courage to take on a fullback on an iso?
The first time I saw Jason Peters in preseason I wanted to make him our fullback.