In football terms, the backfield is defined as either the area behind the offensive linemen or the players who line up behind the line of scrimmage. Players in the backfield are the most important weapons on a team�s offense. The following positions can be found in the backfield:
Fullback – The duties of a fullback are split between blocking and running the football. Known for their power, fullbacks are often called upon in short-yardage and goal-line situations. The NFL once featured many fullbacks as primary ball carriers, such as Jim Brown and Larry Csonka. Those days are past, however.
Quarterback – The player who leads the offense, the quarterback is the most important position on a football team. After taking the ball from the center, the quarterback can elect to run, hand the ball to a running back or pass down the field. Current superstars at this position include players such as Tom Brady, Tony Romo and Peyton Manning.
Halfback – Also known as a running back, the halfback�s responsibilities include carrying the ball out of the backfield, blocking in pass protection and sometimes acting as a receiver. The halfback relies on the offensive line to open holes for him to run through, but superior players can often create their own holes. Today�s top halfbacks include LaDainian Tomlinson, Adrian Peterson and Brian Westbrook.
Slot Back – Mainly found in the CFL and Arena football, the slot back lines up in the backfield and may make a running start at the offensive line (not allowed under NFL rules). In the college level of American football, slot backs are often utilized in Triple Option and flexbone offenses.
Flanker – This wide receiver position lines up behind the line of scrimmage and uses the extra space to avoid being jammed by the cornerback. The flanker is often the star wide receiver of the team.
Slot Receiver – This receiving position lines up between the linemen and the split end or flanker. If lined up on the same side as the flanker, the slot receiver will usually be slightly behind the line of scrimmage. This also allows the slot receiver to avoid jamming when crossing the line of scrimmage.