The most intriguing NFL matchup of Week 14 will start with headsets and end with a handshake.
This game has significant implications for the playoff picture, and few people understand the similarities and differences between the coaches better than Eagles quarterback Mark Sanchez, who has gotten to know Kelly well in recent months and played under Carroll at USC.
"One of the most important things about both of them is people gravitate to them as people and as motivators," Sanchez said by phone this week. "More than just coaches, they're both exceptional teachers.… The real difference is their background. [Carroll is] a West Coast guy, [Kelly is] an East Coast guy. One's offense, one's defense. They're like Pepsi and Coke, both are dominant in their profession."
The only previous time Carroll and Kelly faced each other as head coaches came five years ago, when Carroll was in his final season at USC and Kelly was in his first at Oregon. On that day, the Ducks clobbered the Trojans, 47-20, at the time the Trojans' worst loss in 12 years.
A year earlier, when Kelly was Oregon's offensive coordinator, the Ducks lost to USC, 44-10, a game in which Sanchez threw for 332 yards and three touchdowns.
Even now, there's some back-and-forth ribbing between Kelly and Sanchez about those college days. During last month's Thanksgiving game at Dallas — a 33-10 victory by Philadelphia — the Eagles coach playfully needled his quarterback via Sanchez's helmet radio.
"He's yelling in the headset, just joking around like, 'You USC quarterbacks, you don't know how to run the damn read option! You've never done it!' " Sanchez said.
Even in the pressure cooker of the Houston game four weeks earlier, when Sanchez came off the bench to replace the injured Nick Foles, Kelly used a little radio levity to keep his quarterback loose.
"We had to read a D-lineman on a play, on a keep-or-give," Sanchez said. "[Kelly] was like, 'Hey, you're reading No. 99.' "
Sanchez turned to his coach and shot him an eye-rolling look, as if to say, "Yes, I know. Thank you, Captain Obvious."
Kelly seized the moment to drive home the point with, "No. 99 is named J.J. Watt, by the way."
"Chip loves keeping it light," Sanchez said. "He knows when to be serious, and he knows when to have fun. Everything's fair game. If you say something stupid, kind of fumble with your words a little bit, he's very quick-witted."
Both Carroll and Kelly, Sanchez said, "care about you on and off the field. It's not just football is life and that's it. It's not, play well or get the heck out of here."
Many people remember the uncomfortable news conference when Sanchez departed USC, how Carroll publicly disagreed with the quarterback's decision to leave school early for the 2009 NFL draft. There was talk of a rift between the two.
"We just had a difference of opinion at the time in that regard," Carroll recalled for reporters this week. "I wasn't going to hold him back.… The main thing was, he was really forthright and he was very determined to take on the challenge."
Even as rumors of a falling out began to gather steam in the immediate aftermath of the news conference, Sanchez said, the coach and quarterback were on the phone smoothing their disagreement.
"People thought that I thought he was a real jerk or something," Sanchez said. "I got on the phone to let him know that's not me putting that stuff out there. 'I think you're one of the best coaches I've ever met, probably one of the best coaches I'll ever have.' He's like, 'Are you kidding me? I'm not rooting against you. We just happen to disagree on this issue.'
"I don't even know if either of us was right or wrong. Either way, things were going to be great."
Carroll wants the best for Sanchez, and Sanchez wants the best for Carroll. Every other day but Sunday.