A wingback is a position in football used primarily in an option-style offense as it is a running back who lines up in a different position. A wingback aligns himself usually a yard wider than a tight end and also one yard from the line of scrimmage. In an offense where wingbacks are used, two are used with one on either side of the offensive line. Having wingbacks in an option-style offense also includes a lot of pre-snap motion which confuses the defense as the direction of the run.
A wingback is usually involved in an offense that is referred to as the Wing-T, Wishbone, Option, or Triple Option. By having a versatile wingback or two lined up for every play, this offense may seem simple, however, many different plays can be run out of it. A run-heavy style is usually used based on reads made post-snap by the quarterback. Teams that use the option-style offense have included Nebraska and Georgia Tech while many of the service academies including Army, Navy, and Air Force still use this form of offense. The option offense can be used if teams have a lack of size on the offensive line and with all of the pre-snap motion and post-snap reads it can compensate for this lack of size and speed.
Wingbacks do act as defenders. A 'wingback' is a running back-like position in the 'wing' formation. The 'wing' formation is a broad formation on offense where multiple backs line up in a line behind the line of scrimmage. The wing formation is often used when running the football and can be used to confuse the defense as to which direction the run is going. Navy and BYU continue to use this formation and play style.
Wingbacks work in many different facets, including defender roles. Depending on the play, they can serve as blockers, receivers or runners. He is positioned a yard away from the line of scrimmage near the tight end. The wingback can create different offensive opportunities, whether he passes or runs the ball himself, which can cause the defense to get jammed up and lose sight of the ball. So although the wingback is not a specific position, he works in defensive roles during certain formations that utilize wings and wingbacks.