The quarterback is the player on the football team who is acting as the on-field coach. The quarterback will control the football most of the time, taking the snap from the center, handing the ball to running backs and fullbacks, and passing to receivers on the field. The quarterback is also responsible for relaying plays from the coaches to the players on the field during a huddle. The quarterback is most often considered one of the most important positions on the field.
For a receiver to catch a pass, they must be eligible. There are certain rules that dictate who can be an eligible receiver, we'll discuss that later.
The pocket is an enclosed area on the field in the offensive backfield created by the offensive line to shield the quarterback from being tackled. The pocket gives time for the quarterback to scan the field to find an open receiver to throw to.
A forward pass is the most common type of pass in the game of football. A forward pass must be thrown from behind the line of scrimmage to a player who is ahead of the passer, most often a forward pass takes place between a quarterback and a receiver. If a forward pass touches the ground before reaching a receiver, the pass is called incomplete and the play is over. No more than one forward pass may occur per play and a forward pass cannot be thrown if the passer has passed the line of scrimmage.
A backward pass, or often called a lateral pass, is when the ball is thrown to a player who is behind the passer. A backward pass can occur anywhere on the field and an infinite number of backward passes may occur during any play. If a backward pass hits the ground before reaching a receiver, the ball is still live and either team can recover it.
An eligible receiver is a player who can catch a pass. Eligible receivers wear specific numbers on their uniform to help officials with determining who is eligible. Eligible receivers are:
An ineligible receiver is any player that cannot catch passes in football. Offensive linemen cannot be eligible receivers unless they notify the officials that they intend to be an eligible receiver, and they line up in the appropriate spot on the field to be eligible.
A completion is a pass that is caught by an eligible receiver.
An incomplete pass, or an incompletion, is a pass that is not ruled a catch by an official. Examples of incomplete passes are:
If an official believes any of the above were violated, the pass will be ruled as an incompletion and the play will end.
Simultaneous possession is when two players, one from the offense and one from the defense, both catch and maintain possession of the ball at the same time. If both players were deemed to catch the ball at the same time, and neither loses possession at any point, the ball is awarded to the passing team.
A fumble is a ball that is dropped by the ball carrier. A fumble can be recovered by any player on the field. If a player loses control of the ball while in the process of making a catch, the pass is called incomplete. If the process of the catch is completed then the player loses control of the ball, it is called a fumble.