IRVING, Texas (AP) -- The Dallas Cowboys hired former Tampa Bay defensive coordinator Monte Kiffin as the replacement for Rob Ryan on Friday.
The move signals a switch back to the 4-3 alignment eight years after Bill Parcells implemented the 3-4.
Dallas coach Jason Garrett said he had two days of discussions with the 72-year-old Kiffin and came away believing the Cowboys have the personnel to make the switch work.
The most notable change will be Pro Bowl linebacker DeMarcus Ware becoming a defensive end, and Anthony Spencer could make the same move if the Cowboys re-sign him.
''Monte Kiffin's level of experience and track record of success as an NFL defensive coordinator are unmatched,'' Garrett said. ''He has produced NFL defensive units that have consistently performed at a high level in a scheme that has stood the test of time.''
Kiffin hasn't coached in the NFL since ending a 13-year run in Tampa in 2008. He spent the past four years coaching in college with his son, Lane Kiffin, at Tennessee and Southern California.
At Tampa, Kiffin's defenses frequently were among the league's best, and the Buccaneers won the Super Bowl with him after the 2002 season. That unit was the first in the league since the champion Chicago Bears in 1985 to lead the NFL in total defense, points allowed and interceptions.
''I came away from the interview process with Jason with a feeling that Dallas is the right place to be,'' Kiffin said. ''They're close, and I am confident that there are quality pieces in place for us to be able to get the job done.''
Ryan was fired Tuesday after two seasons. His defenses were inconsistent pressuring the quarterback and didn't force many turnovers. In 2011, the Cowboys allowed the second-most yards passing in franchise history.
This season's injury-filled unit couldn't stop New Orleans quarterback Drew Brees and rookie Washington running back Alfred Morris in season-ending losses that kept Dallas (8-8) out of the playoffs for the third straight year.
The Buccaneers finished in the top 10 in total defense 11 times in 13 years under Kiffin and had streaks of 69 straight games with a sack and 54 with at least one turnover during that stretch. Tampa had 31 interceptions when it won the Super Bowl, nine more than the Cowboys have the past two seasons combined.
Kiffin, who turns 73 next month, has 26 years of NFL experience with other stops in Green Bay, Buffalo, Minnesota, the New York Jets and New Orleans.
He coached 17 years in college before going to the NFL, including 11 seasons under Bob Devaney and Tom Osborne at Nebraska, his alma mater.