Curl-Flat
The fundamental conflict read on the flat defender
The outside receiver runs a 12-15 yard curl while the inside receiver releases to the flat. The curl/flat defender is the conflict player — he cannot cover a 12-yard curl and a flat route simultaneously. The QB reads this single defender and throws opposite his movement. Bill Walsh invented and systematized this as part of his West Coast Offense with the Cincinnati Bengals (1968-75). Joe Montana and Steve Young executed it masterfully with Jerry Rice and Roger Craig.
Route Assignments
Curl route at 12-15 yards — the primary read. Sits down facing the QB.
Flat route — releases inside-out to the flat at 3-4 yards.
Backside spot/hitch at 6 yards — third read if the primary side is covered.
Go route to clear out the backside corner and keep the safety deep.
Check-down releasing to the opposite flat.
Read Progression
Read the curl/flat defender. If he drops to cover the curl, throw the flat. If he drives on the flat, hit the curl sitting behind him.
Why It Works
The curl/flat defender faces an impossible choice — he cannot cover both a 12-yard curl and a flat route simultaneously. The QB reads one defender and throws opposite his movement.