IRVING, Texas — 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.