A practice squad in football are players who are not considered to be on the actual team but play against the starters of a team to help them practice. The practice squad can also be called the taxi squad, as they are not on the active roster, but are signed to the team. There are usually 10 players on a team's practice squad, and a player is only eligible to be on the practice squad for three seasons.
A practice squad typically helps out during training and practices, and is intended to emulate an upcoming team and their strategies. They act as offenders or defenders. Because a team is familiar with each of the player's playing styles, it can be difficult to get the full experience when scrimmaging. Practicing with active roster team members allows the practice squad to train and condition, and further develop their skills to eventually make it on the roster. They also serve as backup players in case of injuries or illness on the team.
Being on the practice squad means getting an inside peek to the team's strategies and training opportunities. Although many people may think the practice squad doesn't mean much, it can lead to becoming much more acclimated with the team environment and being prepared to move up on the roster.