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 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, including Jim Brown, Marion Motley, Jim Taylor, Franco Harris, Mike Alstott, Larry Csonka, John Riggins, Christian Okoye, Levi Jackson, and Marcus Allen.
In the days before two platoons, the fullback was usually the team's punter and drop kicker. When at the beginning of the 20th century, a penalty was introduced for hitting the opposing kicker after a kick, the foul was at first called "running into the fullback", inasmuch as the deepest back usually did the kicking.
Fullbacks are typically known less for speed and agility and more for muscularity and the ability to shed tackles. In the modern NFL, fullbacks, while occasionally deployed as ball carriers, are often primarily a lead blocker to allow running 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 phased the fullback position out of their offense all together, with those teams either all but eschewing the I-formation, or instead utilizing either a tight end, h-back, or backup running back in the role. There are still fullbacks who remaining prominent in the NFL, among them Aaron Ripkowski, Jamize Olawale, James Develin, John Kuhn, Patrick DiMarco, Mike Tolbert, Kyle Juszczyk, and Marcel Reece. However, in spite of their usually infrequent carries in modern NFL offenses, some fullbacks have 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 halfback.
Although technically a running back, typically fullbacks are primarily valued for their blocking in most modern day offenses. The most common and simple runs, the Dive and the Blast, both employ the fullback as the primary blocker to "make way" for the halfback. In the flexbone formation, however, the fullback (sometimes referred to as the B-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 goalline formation. Examples of such players who have been frequently used as situational fullbacks include Haloti Ngata, Dontari Poe, 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 and Nikita Whitlock have played both as a defensive tackle and fullback. Defensive Tackle William "The Refrigerator" Perry scored a touchdown in Super Bowl XX from the fullback position.
Most teams in the NFL do not have a substitute fullback, though there are exceptions. The role can be filled by backup or number three or four tight ends or bigger and less-frequently-used running backs. In modern offenses, fullbacks in an I-formation can be motioned into a 2-TE formation or H-back formation, making a running back or tight end fairly well suited to the role.
The position is less frequently used in Canadian football, which focuses more on passing than running the ball.