Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Marvin Gabriel Cabrera Ibarra (born May 1, 1980 in Mexico City) is a Mexican football defender. He currently plays for Morelia in Mexico. 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.