Who's grades? ESPN's?
Kam is the QB in the 2ndary...having a big time SS is somewhat of a rare occurrence in the NFL, let alone having 2 (ET). What Kam provides at the back-end and what he can do at the line of scrimmage is invaluable IMHO. He strikes fear in the middle of the field which can change the way routes are run. He makes guys around him better that way, too. This may sound like a stretch to some, but if Kam plays against the Rams, our chances of winning that game increase greatly.
This doesn't detract to what MB does...pass rushing is extremely important. But even getting 1 sack a game can be hard to come by (he has never had a sack a game ever average, and had only 7 last year ans has never dipped into double digits)....but big time hits in the secondary are nearly a every game occurrence for Kam, and they can change the way a team game plans. He is the biggest, by far, starting safety in the NFL. He is a LB playing S more or less. That just doesnt happen.