1. Playing Through the Back
A defender cannot come over a receiver’s back to try to play a pass. Be careful not to penalize a defender who actually gets around the side of the receiver to bat down or perhaps even intercept a pass. From the wrong vantage point, it can look like early contact from behind and the official can improperly penalize a good defensive play. Also, don’t throw the flag when the contact by the defender and the touching of the pass by the receiver occur so closely together in terms of timing that one needs a slow-motion replay to see which really occurred first.
2. Hook and Turn
A defender cannot use his arm as a hook to spin the receiver around before the pass arrives. In calling the foul, officials must ensure there is a material restriction; simply placing an arm on the receiver is not enough for a flag. A defender, for example, might drape his arm on a receiver’s waist and reach around the receiver with his other arm to bat down a pass, and there is no foul because the receiver has not been materially impeded in his attempt to catch the pass. Officials must also be careful not to throw a flag if the hook and turn occurs after the ball touches or passes the receiver.
3. Not playing the ball
The rules give defenders and receivers equal rights to try to catch a pass, but for a defender to exercise that right, it follows that he must be looking at the ball. If, while a pass is in the air, the defender is looking at the receiver and contact materially impedes the receiver in his attempt to catch the pass, interference should be called. Officials need to be alert to the tricky defender who plays the receiver, contacts him and then, just after the contact, spins his head around to try to find the ball and avoid an interference call.
4. Grabbing the arm
Interference should be called when a defender grabs the receiver’s arm, such as when he begins to reach up to catch the ball. Sometimes the defender pins one of the receiver’s arms against his body, thus allowing him to get only one arm up to make the catch. That can be very difficult for officials to see. Often, an official substantially farther away from the action has the best look and can make the call.
A defender who is not playing the ball cannot veer into a receiver’s path and make contact. That particularly occurs on sideline routes when the defender and receiver are running in close proximity and the defender uses his body to force the receiver out of his route. It can be a subtle move, but remember that it doesn’t take much to disrupt a receiver’s route and prevent him from getting where he is trying to get to in order to catch a pass.
6. Early contact
That type of interference sometimes occurs on passes over the middle, when a linebacker or safety comes up to make a hit on a slant route or crossing route. It is very often a bang-bang play and officials are challenged to determine which came first: the contact or the arrival of the ball. But that category of interference can occur anytime receivers and defenders are in close proximity when the pass arrives.