1) Backfield exchange 2) Exchange in a pocket 3) Football play 
The action of the ball being given to another player, most often the running back.
(from the article `telephone and telephone system`) ...the course of a call, a central controller automatically reroutes the call from the old cell to the new cell without a noticeable interruption in ...
see handover.
[n] - a football play in which one player hands the ball to a teammate
noun (American football) a play in which one player hands the ball to a teammate