I try to get in their heads when they're tired and see how they do when they're fatigued. It's a character check. I grab hold of a guy and see if I can wear him out. I'm looking for a guy who completely folds. Warren never folded.
Some guys are great testers.
I want to see how they do on the field. He does that. He makes plays. That's more important than any test you can give. He's a great football player.