and then we have this in 2012:
only two teams -- the Bears and Vikings -- consider the cover 2 to be their base defense. Most teams are switching to more combination man coverages, in part to combat the two-tight-end sets growing in popularity (see sidebar).
But an even bigger reason for the demise of the cover 2 is the rapid rise of defensive penalties called for big hits.
http://espn.go.com/nfl/story/_/id/83...-espn-magazine