Presiding over the worst defense in Dallas Cowboys has earned Monte Kiffin a new job title.

Kiffin was named assistant head coach/defense on Tuesday night, while Rod Marinelli was promoted to defensive coordinator.

The Cowboys switched from the 3-4 to the 4-3 scheme with the hiring of Kiffin last year but finished last in the NFL in defense, allowed the most yards in franchise history and the second-most points in franchise history.

A master of the 4-3 scheme, the Cowboys hoped Kiffin could rekindle the magic he had for so long with the Tampa Bay Buccaneers as they moved from the 3-4. It never happened. The Cowboys hope Marinelli will have the same impact he had running the Chicago Bears' defense from 2010-12. The Bears forced the most fumbles (59), intercepted the third-most passes (65) and scored the most defensive touchdowns (13) in those three years while allowing the fourth-fewest points (904).

"Rod Marinelli's production in terms of creating turnovers and changing field position as a defensive coordinator is well documented," coach Jason Garrett said in a statement from the Cowboys. "Monte Kiffin's overall knowledge and understanding of this defensive scheme will be put to use in mentoring all of the players and coaches on the defensive side of the ball. Monte was brought here to direct a transition in philosophy to the 4-3 scheme, and he will continue to oversee the development of our defense in this scheme."

The Cowboys had injuries in 2013, losing players like Sean Lee, DeMarcus Ware, Morris Claiborne and Anthony Spencer for multiple games. They never had Jay Ratliff, who was cut in October. They also had subpar seasons from players they needed to play well, like Brandon Carr and Bruce Carter.

After the season-ending loss to the Philadelphia Eagles, Kiffin said he was not ready to retire and wanted to continue to be with the Cowboys. At the Senior Bowl last week owner and general manager Jerry Jones said Kiffin and Bill Callahan will return in 2014, but they will both be in different roles.

The Cowboys named Scott Linehan the passing game coordinator and will take over the play-calling duties from Callahan, who handled the job in 2013. Callahan will continue to hold the offensive coordinator/offensive line title.