RENTON, Wash. – Back in 2010, when Chip Kelly still was the coach at Oregon and Pete Carroll was in his first season as the coach of the Seattle Seahawks, Kelly made a friendly visit to Seattle to talk with Carroll and watch a Seahawks practice.

Neither man knew then, of course, that Kelly would become the head coach of the Philadelphia Eagles three years later and Carroll’s team would win the Super Bowl when Kelly was a rookie NFL coach.

After being foes in the Pac-12 (Pac-10 in those days), they face each other for the first time in the NFL on Sunday in Philadelphia. Both Kelly and Carroll remember that day at practice four years ago.

“I’m sure [Kelly] regrets that tremendously, because of all the things that he shared with me," Carroll joked.

And what about all the things Carroll shared with Kelly? Carroll said he doesn’t reveal too much in those situations.

“You don’t know who the guy’s best friend is sometimes,” Carroll said, smiling. “So yes, you do have to be careful about that. We scrutinize carefully there. That’s why when our coaches were talking to [Kelly], they stood away from the field so he had to look away from the practice and he didn’t get to watch. Just competing -- a little strategy there.”

Kelly said he wasn’t there to scrutinize every play the Seahawks were running.

“It really wasn’t an interest in Seattle, per se,” Kelly said. “When you’re a college coach, you take a lot of visits during the spring and you watch people during the spring practice, but I always wanted to visit people in-season. You obviously practice different in the spring than you do in the fall.

“I was just fortunate. I knew Pete from the Pac-12 and I couldn’t visit any other Pac-12s in-season, so I visited a lot of schools. I visited Air Force, I visited Seattle, I went to the 49ers with Jim Harbaugh. I just wanted to watch a team practice when we had a day off.”

Kelly is 19-9 in his two seasons with the Eagles, including 9-3 entering Sunday's game, which has major playoff implications for both teams. So what is it that has made three guys who coached against each other in the same college conference (Kelly at Oregon, Carroll at USC and Harbaugh at Stanford) become so successful in the NFL?

“I don’t think you can paint a brush and say it because they’re from this conference or college or whatever,” Kelly said. “When you talk about Jim and Pete, those are two outstanding coaches -- I don’t care what level they coach at. No matter where they coach, I think they would be successful.”

Carroll said Kelly has done the same thing, proving that his faced-paced offense at Oregon could work in the NFL.

“I think coaches can coach on any level,” Carroll said. “They just have to work to adapt. Our game isn’t that much different. It’s not as different as you may think and Chip has demonstrated that. He’s done a great job of illustrating the flexibility in his style, and it’s not a college offense. It’s an offense that comes out of college and it certainly applies here.”