Because we are in zone 85% of the time. Complex zones I should add as well. Our shell will never reveal to the offense where the double team is coming from, nor which coverage we are in, except when we play man.
At the snap of the ball, the cover 2, becomes a cover 3 or 4 or some variation thereof.
The key to the game defensively is how does BB take away the TE/RB check downs that killed us in the second half last year, without sacrificing anything deep?