Sweeper is the name of a defensive position in soccer. Generally used with a three or four (marking) back system, the sweeper plays behind the main line, always keeping in a triangle off the other two backs, and about five yards off at an angle from whichever marking back is being pressured. The sweeper is basically the last line of defense, and if a marking back is beaten, it is his/her job to "sweep" back and either stop or delay the run, allowing the rest of the defense to recover.