A pass route used by an offensive receiver in which they will start downfield for a short while before turning back towards the quarterback to receive the pass. Ideally, a curl will keep the defense off balance since they have to respect the receiver's ability to continue the route deep, allowing the receiver to come back and receive the pass. Typically, curls are short routes to gain small amounts of yardage and sustain a drive rather than gain huge amounts of yardage.
The curl is one of the basic routes used by a passing offense. Curls are considered safe routes since they are short and thrown directly to a receiver who is facing the quarterback. Ideally, the route before the curl will force the defender backward and give the receiver space to come get the ball. The quarterback can assist the defender by throwing the ball early in the curl so that the defender does not have time to react.