Playbook: Cover-1

This coverage scheme relies on a single high safety and underneath defenders in man coverage. If executed properly, Cover-1 is good against both the pass and the run, as it has the advantage of being able to use an eight-man front (should the strong safety drop into the box).

Cover-1 relies on sound technique from the corners and a smart, fast free safety with great range. The corners play with outside leverage and attempt to funnel their assignments into the middle toward the free safety.

In man coverage, the corners often play press-man, though in the image above they're shown in off coverage. The outside linebackers will cover the running back(s) or use a "green dog" technique (man coverage, add to the rush if their assignment blocks).

Finally, the MIKE linebacker will typically drop into the underneath hole (below the free safety) or occasionally blitz. Dropping into the underneath hole (typically called Cover-1 Robber) gives the defense two levels of zone coverage in the middle, where the corners will be forcing the receivers by using an outside shade. Here's another look at Cover-1 Robber on the chalkboard:

Outside References

1) NFL 101: Introducing the Basics of Cover 1

2) Why Pressure Sells for Patriots on 3rd Down
3) Cover 1 Robber Defense 
4) Football Fundamentals: Cover 1 Defense
5) Football Fundamentals: Cover 1 Defense Adjustments 
6) Press Man Coverage Technique 
7) 4-2-5 Cover 1 (Man Free) Coverage
8) Cover 1 (Man Free) Technique
9) Cover 1 (Man Free) Versus Action Passes
10) Cover 1(Man Free) Versus Mesh Route