The sweeper is a position on a soccer team. It is versatile type of defender who ‘sweeps up’ the ball if an opponent manages to breach the defensive line. He is more fluid than other defenders who man-mark their designated opponents. Because of this, the position is sometimes referred to as libero; from the Italian word meaning ‘free.’
Though the sweeper may be expected to build counter-attacking moves, and as such requires better ball control and passing ability than a typical back, his or her talents are often confined to the defensive realm. In modern football, its usage has been fairly restricted, with few clubs in the biggest leagues using the position.
The Daily Omnivore 