As everyone who knows me knows, I have been evaluating football players for a long time. It's been 42 years since I started making a living doing evaluations. In that time, two positions took me longer to learn how to evaluate and feel comfortable evaluating them: offensive linemen and defensive backs.
When I started out, I was looking mostly at the player's production — meaning, did he win or lose each rep? As I became friends with many offensive line coaches, I began to pick their brains to really learn the nuances of the position. The first thing I learned was I couldn't evaluate a tackle the way I evaluate a guard or a center.