Cover 3 Defense

How Cover 3 Works

The corners and the post safety take the deep thirds. Underneath, a Curl/Flat defender on each side (in Crucible's diagram the strong safety and the Sam) and two Hook/Curl defenders (the Will and Mike) split the field.

The Hook/Curl defenders drop to landmarks around the hashes, read your drop and break on the ball. The Curl/Flat defenders carry a receiver who runs up the seam, or widen to the flat when nothing goes vertical.

Where Cover 3 Is Weak

• The seams. The Curl/Flat defenders have to carry vertical seams, which opens the flats and curls underneath.
• Curl and flat. The Curl/Flat defender cannot cover both, so throw the one that defender leaves.
• Sail: three receivers at three levels to one side outnumber the two defenders on that side.
• The deep comeback. Corners bailing to their third are soft on routes that stop at 15 yards and come back to the sideline.

How to Recognize It

• One safety deep in the middle: MFC (Middle Field Closed), a defender inside or approaching 15 to 18 yards deep between the hashes.
• Corners off the ball, usually around 7 yards or deeper, with outside leverage.
• The other safety down near the line, often to the strength of the formation.
• Motion gets a bump or slide from the underneath defenders. Nobody runs with the receiver.
• At the snap the corners bail to their deep thirds, the post safety backpedals, and the underneath defenders drop with their eyes on you.
• Cover 1 shows the same one-high shell. Corners bailing with their eyes on you is Cover 3. Corners turning to run with a receiver is Cover 1.

How a QB Reads It

Throw off the defender your concept puts in a bind, often a Curl/Flat defender with two receivers to cover. Seams test the post safety and the Curl/Flat defenders who carry them. Against bailing corners, the hitch and comeback are there on time.