A live ball is a ball in play. A pass, kick or fumble that has not yet touched the ground is a live ball in flight.
A dead ball is a ball not in play.
A loose ball is a live ball not in player possession during:
A running play.
A scrimmage or free kick before possession is gained or regained or the ball is dead by rule.
The interval after a legal forward pass is touched and before it becomes complete, incomplete or intercepted. This interval is during a forward pass play, and any player eligible to touch the ball may bat it in any direction.
All players are eligible to touch, catch or recover a fumble (Exceptions: Rules 7-2-2-a-Exc.2 and 8-3-2-d-5) or a backward pass.
Eligibility to touch a kick is governed by kick rules (Rule 6).
Eligibility to touch a forward pass is governed by pass rules (Rule 7).
When Ball Is Ready for Play
A dead ball is ready for play when:
With the 40-second play clock running, an official places the ball at a hash mark or between the inbounds marks and steps away to his position.
With the play clock set at 25 seconds, or at 40 seconds after an injury to or loss of helmet by a defensive team player, the referee sounds his whistle and either signals to start the game clock [S2] or signals that the ball is ready for play [S1]. (A.R. 4-1-4-I and II)