Libero (soccer)

In the sport of association football, a defender is an outfield player whose primary role is to prevent the opposing team from scoring goals.

There are four types of defenders: centre-back, sweeper, full-back, and wing-back. The centre-back and full-back positions are essential in most modern formations. The sweeper and wing-back roles are more specialised for certain formations.

A centre-back (also known as a central defender or centre-half) defends in the area directly in front of the goal, and tries to prevent opposing players, particularly centre-forwards, from scoring. Centre-backs accomplish this by blocking shots, tackling, intercepting passes, contesting headers and marking forwards to discourage the opposing team from passing to them.

With the ball, centre-backs are generally expected to make long and pinpoint passes to their teammates, or to kick unaimed long balls down the field. For example, a clearance is a long unaimed kick intended to move the ball as far as possible from the defender's goal. Due to the many skills centre-backs are required to possess in the modern game, many successful contemporary central-defensive partnerships have involved pairing a more physical defender with a defender who is quicker, more comfortable in possession and capable of playing the ball out from the back; examples of such pairings are John Terry and Ricardo Carvalho with Chelsea, Nemanja Vidić and Rio Ferdinand with Manchester United, or Giorgio Chiellini, Leonardo Bonucci and Andrea Barzagli with Juventus.

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Wikipedia