All football teams consist of offense, defense and special teams, and all three positions have specific duties they have to do within a game. The top three positions on defense, also the most important, are cornerback, linebacker, and defensive line. On the defensive side, cornerback tends to be the most popular and important player, both in college and NFL levels. The cornerback has many responsibilities, one of which is guarding the player who is sent out to catch the ball that is thrown to him. If you are the best cornerback on your team, you tend to guard the best ‘receiver’ on the opponent's team. On a typical football team, there is usually 2 starting cornerbacks, but others will come in the game depending on the number of receivers
