Right. At least demonstrate you can succeed in a role in which you have to do almost all the things HC's have to do, just on one side of the ball. And though there's still a big gap between position coach and coordinator, you have a mentor that can guide you, show you your weaknesses, and help you get to the next level. But, from what I've seen of Mayo, I am convinced he would fail as DC. He's just not smart enough. He's a poor strategist, and too slow on his feet to be a good tactician when the scope of responsibility is broad. He was great at diagnosing a play and getting the defense ready for it when he was on the field, but that's a narrow scope of responsibility compared to what a DC has to do.