PHILADELPHIA -- The Philadelphia Eagles did everything they could to distance themselves from the Chip Kelly era. They hired the anti-Chip in coach Doug Pederson, overhauled two-thirds of the roster, and pushed the eject button on Sam Bradford while shaping a new identity around their hand-picked quarterback, Carson Wentz. But in order to advance to the Super Bowl after Wentz went down, they had to take a major page out of Kelly's playbook to reconstruct his greatest masterpiece -- the 2013 version of Nick Foles.

He appeared out of thin air Sunday, dropping dimes all over the field in a 38-7 Eagles win over the Minnesota Vikings in the NFC Championship Game. Foles completed 79 percent of his throws and tossed three touchdowns to zero interceptions for a quarterback rating of 141.4 against the best defense in football. What seemed like a sudden, out-of-the-blue performance was actually the fruits of furious behind-the-scenes work aimed at harnessing some of that '13 magic, when Foles threw 27 touchdowns to two interceptions in Kelly's first year in the pros.

During their first-round bye, Foles and the coaching staff sifted through old film to figure out the concepts and style that fit him best following struggles down the stretch. One of the key takeaways was Foles is at his best when he's making quick, defined reads and playing fast.

"Sometimes the hardest things are just the simple things," Foles said, "like basically get out of your own head and go play the game you know how to play."

Nothing solves that quite like a Kelly offense, which simplifies the job of the quarterback in order to run tempo at break-neck speed. A centerpiece of that system is the run-pass option, or RPO, in which a pass option is built into a running play, allowing the quarterback to pull it depending on how the defensive player that he's reading reacts.

"Some of it is very creative and unique and great to our game, obviously. It takes into consideration that you don't have to block everybody -- RPOs, for instance. It was all a new world for me," Pederson said. "Kansas City was the first time I was exposed to it through Alex Smith [in 2013] when he came from San Francisco where he did it. So I think it's something that's innovative, it's new, it's fun for the guys, but at the same time, I want to make sure that it fits us and fits our personality on offense."

The option plays have evolved over the past five years. Early on, there was a lot more zone read, in which the quarterback keeps the ball and runs if the player being read aggressively crashes down on the running back. You can still find the zone read, but quarterbacks are simply too valuable to over-expose them in the running game. The "run" in RPO is about the running backs these days as opposed to the signal-caller.

"Everybody thinks RPO, they think young, athletic college quarterback -- and that's not what the RPO game is all centered around," offensive coordinator Frank Reich said. "It's centered around accurate throwing, good decision-making and good execution. When we use it, Nick has shown a great aptitude of doing that very well."

The passing routes have expanded as well, developing beyond a simple bubble screen. ESPN NFL analyst Matt Bowen pointed to a third-and-1 against Minnesota as an example, during which Pederson designed a pick play to take care of Ertz's would-be defender as the tight end shoots into the flat:

"That's quick game plus a run. And that is nasty for a defense," Bowen said. "It's nasty."

RPOs were a part of Pederson's offense before Foles took over -- Wentz executed them effectively, and added an extra element as a run threat -- but Bowen agrees that there's been an uptick with Foles at the controls.

"That's smart coaching, first of all. It's not putting the player in your scheme, it's building the scheme around your player," Bowen said. "He's well-rehearsed in those mechanics because he's worked with Chip."

Added NFL Films executive producer Greg Cosell: "It's a great thing to run with Foles because you're trying not to expose his limitations. That's all one-read stuff, so it's really simple, low-risk throws."

Bowen predicts a heavy dose of this style of offense on Feb. 4 against the New England Patriots.

"I would do a bunch of them against New England because New England has struggled against RPOs in the playoffs," he said. "So if I'm Philly, I run them like crazy in Sunday night's game and see what Coach Belichick's done in the two weeks to adjust. What's his plan to take away these RPOs? I want to find out immediately. Because if they don't have a plan that's going to stop them entirely, I'm going to run them a lot."

One of the reasons for Kelly's downfall in the pros was his unwillingness to adjust and expand. Defenses eventually caught up to him, and he didn't have a sufficient counterpunch. Coaches like Pederson have added a little more complexity and variance, while being sure not to overuse it in fear of being predictable. It's just part of an expansive playbook.

For all the resistance that Kelly met at this level, though, it's hard to deny his influence on offensive approach.

"Chip Kelly has a hand in modernizing the NFL. There's no doubt about it," Bowen said. "Anyone can have different opinions about Chip Kelly as a head coach and how he managed a team. I understand all that stuff. But in terms of his offensive philosophy and his scheme and the ability to play fast and attack defenses, there's no doubt that he's played a role in modernizing the league. Just look at the playoffs. They're all over the place."

And now here are the Eagles, who did everything but scrub down the walls when Kelly left, leaning on some of the concepts he helped popularize to bring the best out of Foles during a Super Bowl run. It's hard to miss the irony.