With Kelly as Eagles head coach, it's clear that the offense has Kelly's imprints and the defense is more in the hands of defensive coordinator Bill Davis. Kelly calls the offensive plays, and spends much of his practice time with the offense. That's why the most important hire Kelly made was Davis, who seems to have autonomy like Aliotti.
"At the end of the day, what Chip wants, I will give him," Davis said. "We talk often. He's very easy to work with and understand. A very clear communicator. You know exactly where he stands and what he wants and you give it to him. So far, the real tests haven't come yet. The real games, when they start coming, we'll collectively solve problems."
Whenever a defensive lineup decision was broached during news conferences this preseason, Kelly often cited it as Davis' call. When Brandon Boykin played in the slot in the first game, Kelly said that's how Davis wanted it. When the safeties rotated, it was because of Davis' evaluation.
Kelly and Davis meet daily. Kelly is a major part of the personnel evaluation process and discusses the game plan and installation. But the defensive players say that Davis is the one coordinating the defense, while the offensive players note the offense as Kelly's.
"I'm more involved in the offensive side of the ball from a practice standpoint with those guys," Kelly said. "But I watch all the tape from a film standpoint and meet with the staff and talk to those guys constantly on a day-to-day basis."
Kelly's defensive influence is most felt with the philosophy and the evaluation. The type of defense the Eagles run - a hybrid that will likely end up a 3-4 base during Kelly's tenure - comes from Kelly's direction. The body types he likes at positions comes from Kelly, and that's a big change on defense compared with Andy Reid's tenure.
Kelly has also seen a variety of defensive looks trying to stop his offense, so he has a sense of what works. He noted how unique the offense is, and he wants a defense that gives a majority of teams the Eagles face problems. But the 3-4 defense is becoming increasingly popular in college football because of spread offenses – Utah coach Kyle Whittingham said the 4-3 is "becoming a dinosaur" – so it makes sense that the Eagles are transitioning to that front under Kelly.
Kelly said certain principles must remain in any defense. He identified the ability to recognize and diagnose a play, gang tackling, and creating turnovers. That's more a reference point for what he wanted the Eagles to look like than the schemes teams used against Kelly's offenses.
The transition to a 3-4 will take more than one season, and Davis has been open about this. The Eagles added five defensive starters in free agency this year, although they drafted an offensive player with three of their first four draft picks. This was also perceived as Kelly's offensive-oriented approach, although the team insists it went with value on the board instead of position needs. But even the team admits that the offense is ahead of the defense.
"When we went back and studied the teams that won, they had a strength. They're not just in the middle on both sides of the ball," general manager Howie Roseman said. "When we looked at our offense and looked at where we had players rated in the draft, we saw there was an opportunity to really strengthen positions there that would really help us be successful on offense."
What's clear is that the NFL's coaching trend is on offense. Seven of the eight new NFL coaches have offense-heavy coaching backgrounds. The college coaches who most piqued NFL interest - Kelly and Syracuse's Doug Marrone, along with Penn State's Bill O'Brien, Notre Dame's Brian Kelly, Stanford's Davis Shaw, and Texas A&M's Kevin Sumlin - also have experience that favors the offensive side of the ball.
Although it's true the Eagles didn't hire Kelly for his offensive system, his coaching success has come with an offense-heavy approach. But how his defenses perform will also dictate his NFL success, even if Kelly is less hands-on in that area.
Contact Zach Berman at email@example.com. Follow on Twitter @ZBerm.