- The NFL uses a rule book that strictly defines all aspects of a football game from the time limits, coin toss, kicking rules, player lineups and actions during the game.
- During the early days of the NFL, the rules were the same as college football. But starting in 1933, the league began to make modifications to highlight the different aspects of game play of the professional sport.
- Rules are ultimately enforced by the NFL commissioner. This position was integrated into the league in 1941, replacing the position of presidency. The commissioner has the ability to overrule most decisions and routinely addresses rule change propositions.
- The people responsible for enforcing the NFL game rules are known as officials. There are seven officials--referee, umpire, head linesman, line judge, back judge, field judge and side judge--during a game and each performs different duties but ultimately enforce the rules.
- Any time a rule is violated, a foul is called. This results in a penalty levied against the offending team. Officials throw a yellow flag to signal the penalty. A penalty usually means the ball is moved to punish the team.
