A curl route, also called a hitch or hook (sometimes a button hook), is a pattern run by a receiver in American football, where the receiver appears to be running a fly pattern but after a set number of steps or yards will quickly stop and turn around, looking for a pass. This generally works best when the defending corner or safety commits himself to guarding the fly and is unable to stop quickly enough to defend the pass. A "curl out" on the sideline is often referred to as a comeback route.
The curl is a pattern used frequently by the West Coast offensive scheme, where quick and accurate passes are favored.
This route can also be used in what is called a screen, where while the receiver is receiving the pass, one or more linemen, tight ends, or running backs will run in the direction of the receiver in order to block the initial pursuing defenders so that the receiver has time and space to be able to run after the catch.