Why did Kiffin leave USC for Dallas?

Curious to know when Dallas Cowboys defensive coordinator Monte Kiffin knew his time coaching USC’s defense was coming to an end?

His son, USC head coach Lane Kiffin, said it came during a conversation the two men had after Oregon defeated the Trojans 62-51 on Nov. 3, four games before USC’s season concluded.

“When you come to this conference now, you see things you don’t see in the NFL. That’s not an easy thing to do,” Lane Kiffin said, via Mark Saxon of ESPNLosAngeles.com. “If you’ve gone 25 straight years of playing this certain scheme, now all of a sudden you play someone totally different, those rules and things suddenly don’t necessarily transfer over.”

Oregon’s coach at the time of the defeat was Chip Kelly, who has since left the Ducks to become the head coach of the Philadelphia Eagles, a team Monte Kiffin will face at least twice a year in his new gig.

Lane Kiffin also said his father had a difficult time adjusting to the NCAA rule limiting the amount of time a coach can work with his players.

“He’s an old-school coach now,” Lane Kiffin said. “He sleeps in the office. He doesn’t understand what a vacation means. He needs more time with the players because there are so many little rules in his defense to teach the guy. I don’t think we played really fast on defense, and that’s because we were thinking too much.”

Wait, wasn’t Rob Ryan fired because he was implementing too much on defense?

Follow Jon Machota on Twitter: @jonmachota