I don't know this, but I'd be interested in seeing the breakdown between how many times he was "chasing someone from behind" on man coverage vs. zone coverage, and then his assignments on both. I'll give him a complete pass if he was assigned a different zone and hustled over to make a tackle or even get close to the play. Same with man-to-man if he was tasked with a TE or covering someone over the top and then breaking off to make a tackle.