Diaz spent the 2014 season with the Bulldogs (9-5), overseeing a unit that finished 35th in total defense (362.5 yards allowed per game) and 39th in scoring (24.7 points per game). Those marks were improvements from the 2013 season, when Louisiana Tech finished 70th in total defense (408.3 yards) and 61st in scoring (26.3 points).
Louisiana Tech ended its season with a 35-18 victory over Illinois in the Zaxby's Heart of Dallas Bowl on Dec. 26.
Diaz is familiar with Mississippi State after spending the 2010 season as MSU's defensive coordinator under head coach coach Dan Mullen. That season, Mississippi State finished 49th in total defense (356.8 yards) and 21st in scoring (19.8).
Diaz left Mississippi State in 2011 for Texas, where he was the defensive coordinator until he was removed from the position by head coach Mack Brown in 2013 after the Longhorns finished 69th in total defense (407.2 yards) and 57th in scoring (25.8 points). Brown was bought out of his contract after that season.
Mississippi State's defensive coordinator position was vacated last month when Geoff Collins left for the same position at Florida.
Mississippi State (10-3) finished its season with a 49-34 loss to Georgia Tech in the Orange Bowl. MSU finished 87th in total defense (424.4 yards) and 23rd in scoring (21.7 points).
- Mike Fiammetta