Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Javier David Muñóz Mustafá (born 11 June, 1980 in Firmat) is an Argentine footballer playing for C.F. Pachuca. He has the dubious distinction of being the only player to receive two red cards in the same edition of the North American Superliga. Within the sport of association football, a defender is an outfield player whose primary role is to prevent the opposition from attacking. There are four types of defender: centre back, sweeper, full back, and wing back. The centre back and the full back positions are essential in most modern formations. The sweeper and wing back roles are more specialized for certain formations.