What is a fair catch in the NFL and why do players need to do it?
A player can signal for a fait catch by waving his arm in the air. When he does this, it means that a player cannot interfere with him when he goes to catch the ball. Once the ball is caught, the play is dead and the player can not advance the ball.
This is done so that the player doesn't get destroyed by another player while trying to catch the ball. If the player signals for a fair catch, however, and then muffs the return, the ball is live and the other team can attempt to recover it.
NFL fair catch rules
The NFL did approve a new fair catch rule this past May, however. According to Cody Benjamin of CBS Sports, "Under the refined regulations, kick returners can now signal for a fair catch anywhere inside their own 25-yard line, resulting in a touchback that starts the ensuing possession at the 25."
It's worth noting that this new rule is only temporary. The league is doing a one-year trial run and it's a rule that is a win for player safety. It does appear, however, that the NFL is slowly trying to eliminate kickoffs and this move is yet another example of that.