In San Francisco, he'll have many attractive pieces to work with. Aldon Smith, NaVorro Bowman, Patrick Willis, Chris Borland and Antoine Bethea form the nucleus of one of the most talented defenses in the NFL. The Niners ran a 3-4 scheme under Vic Fangio, and are likely to stick with it; Mangini ran a 3-4 during his time with the Jets and Browns.