Fullback (American football)
A fullback (FB) is a position in the offensive backfield in American and Canadian football, and is one of the two running back positions along with the halfback. Typically, fullbacks are larger in size than halfbacks and in most offensive schemes their duties are split between power running and blocking for both the quarterback and the other running back.
Many great runners in the history of American football have been fullbacks, notably Marion Motley, Jim Brown, Franco Harris, Mike Alstott, Larry Csonka, John Riggins and Steve Van Buren. Fullbacks are typically known less for speed and agility and more for muscularity and the ability to shed tackles. In the modern NFL, fullbacks are not usually deployed as ball carriers but are mostly used as a lead blocker to allow smaller, quicker backs to get to the secondary of the opposing team's defense. In the early 2000s, many NFL teams used blocking fullbacks, such as Tony Richardson and Lorenzo Neal, with great success. These backs cleared the way for some of the decade's great running backs. Recently, some teams have actually phased-out fullbacks altogether in favor of two tight end sets. The remaining prominent fullbacks in the NFL such as John Conner, Bruce Miller, John Kuhn, Jerome Felton, Anthony Sherman, Darrel Young, Marcel Reece and Henry Hynoski are still employed as lead blockers and do not carry or catch the ball that often. However, in spite of their usually infrequent carries in modern NFL offenses, some fullbacks have actually led their team in rushing. Notably Le'Ron McClain was the rushing leader for the Baltimore Ravens in 2008 and Tony Richardson led the Kansas City Chiefs in rushing in 2000. Giants running back Peyton Hillis started his NFL career as a fullback before being reverted into a running back.
Although technically a running back, typically fullbacks are primarily valued for their blocking in most modern day offenses. In the flexbone formation, however, the fullback (sometimes referred to as the A-back) can often be used as the primary rushing threat. In many other offensive schemes, the fullback is used as a receiver, especially when the defense blitzes. In selected plays, some teams will have a defensive lineman report as an eligible receiver to line up as a fullback ("Jumbo" or "Heavy Jumbo") or tight end in a "Miami" package in goal-line formation. Examples of such players who have been frequently used as situational fullbacks include Haloti Ngata, Jared Allen while with the Kansas City Chiefs, Richard Seymour while with the New England Patriots, and Isaac Sopoaga while with the San Francisco 49ers, while Dan Klecko had played both as a defensive tackle and fullback. Famously, defensive lineman William "The Refrigerator" Perry scored a touchdown in Superbowl XX from the fullback position.
Most teams in the NFL don't have a substitute fullback. The role can be filled by backup or number three or four tight ends or bigger and less-frequently-used running backs. It could be due to full backs in an I-formation can be motioned into a 2-TE formation or H-back formation.
The position is less frequently used in Canadian football, which focuses more on passing than running the ball.