Can the 1st or 2nd string quarterback come back into the game after the 3rd string quarterback came into the game?

Answer 1

The NFL used to have an "emergency quarterback" rule.

A team was allowed to dress only 45 active players for a game. However, they could also dress a 46th player as a third-string quarterback, with the understanding that the player would be inactive until the fourth quarter.

In the event of an "emergency" where the third QB was forced to enter the game prior to the fourth quarter, the first two QBs would become inactive and could not reenter the game.

This rule was abolished in 2011. Teams can now dress 46 players and there is no "emergency" QB.

Answer 2

That depends on a couple of factors.

1) If the 3rd string QB is one of the players named to the 45 player game day roster, there are no restrictions concerning when he may play and whether the 1st and 2nd stringers cannot play if he does play.

2) If the 3rd string QB is named the 'emergency' quarterback, he is considered the 46th active player for the game. Basically, he is dressed in case of an emergency situation should the first two QBs get injured. If he enters the game prior to the 4th quarter, neither the 1st nor 2nd string QBs are allowed back in the game. If he enters the game in the 4th quarter, both the 1st or 2nd string QB may reenter the game.

Answer 3

Yes, players enter the game at the coach's discretion.