Some teams try to blitz; some teams drop extra players into coverage. There's no one way teams try to stop him, and there's no one way teams can stop him.
"I have no intention of ever being a defensive coordinator, and I couldn't give you an answer on that," Manning said.
Manning has thrown for 60,630 career yards and has 448 touchdowns. At 37, he's on pace for his best season. Manning is the first player in NFL history with 12 touchdown passes in his first three games, and the Broncos lead the NFL in yards and points. It's up to Davis and the Eagles to figure out a way to slow him if they want to avoid slipping to 1-3.
"I've studied a lot of different defensive coordinators, how they tried to stop Peyton," Davis said. "The teams that beat them execute their defensive techniques and they get turnovers. Turnovers are the part, if you're going to have success against a Peyton Manning offense, or slow it down at least."
When the Eagles won
One game that Davis studied was from Nov. 7, 2010. It was the only time in four games against Manning that the Eagles beat him.
The Eagles came off a bye week, when Andy Reid was especially adept (until last season). But it was also the finest moment of Sean McDermott's stint as defensive coordinator. McDermott was so consumed by the game plan that he was actually the scout-team quarterback that week, mimicking Manning's motions because he had obsessed over the Colts quarterback.
"We shut down their run game and made them one-dimension, which was beneficial to us," veteran safety Kurt Coleman remembered this past week. "What we did well on defense was we were able to change up our looks the entire game."
The Colts were undermanned that afternoon, but they were outplayed by the Eagles. Manning finished with 294 yards, one touchdown, and two interceptions. His 67.0 quarterback rating was among the bottom 15 percent of his career.
The two interceptions and varied looks were the key. Asante Samuel, who made both interceptions, said after the game that "once he figures you out, he dissects you."
Dick Jauron was a veteran assistant on that Eagles staff, and was the defensive coordinator in Cleveland last season. Davis was his linebackers coach. When the Browns played the Broncos last season, they spoke extensively about the 2010 Eagles-Colts game. That's one of the reasons Davis looked at that game this past week.
"There's really nothing new," Davis said. "You're not inventing coverages out here. It's really about how you're putting some pressure on him. You have to get around him, not let him get in rhythm like most offenses. Then the way you play your coverages, have to be on point, be where you're supposed to be, right technique in order to have success."
Coleman said that Manning excels at finding the weakness before the snap and immediately exploiting it. That's why Manning is seldom sacked, even though he lacks mobility. So if defenses can change their looks and keep him from exploiting what he sees, he might need to hold the ball for an extra second.
"All week you know it's Peyton, it's Peyton; you know what type of quarterback you're going against," safety Nate Allen said. "But once you get across that line, he's not God or anything. You just got to go play ball."
Allen didn't watch the 2010 film. And it probably won't help. Manning emphasized that was a long time ago, and his second NFL life includes different players and an evolved scheme.
"I think this Denver Broncos team is better than the Indianapolis team we played," Coleman said.
And that's the other problem the Eagles face Sunday.
More than Peyton
Manning deservedly receives the attention, but what has made the Broncos so strong is the diversity of offensive weapons. Demaryius Thomas and Eric Decker were both 1,000-yard receivers last season and are ascending players. They're complemented by Wes Welker, who is the finest slot receiver in the past decade, and Julius Thomas, an emerging tight end who is in his first year as a starter.
Each pass catcher has at least 190 yards and a touchdown this season, so defenses cannot key on containing one. And with all the attention that has gone to stopping Manning this week, game plans can also be devoted to Welker's work in the middle of the field or the mismatch that Julius Thomas presents for a unit that struggles against tight ends.
"A lot of people try to play [Manning] and overdo it and they end up being out of position and can't make plays," middle linebacker DeMeco Ryans said. "It's not just about getting into a game with Peyton. It's all 11 guys."
The addition of Welker and Julius Thomas to the lineup has added different dimensions to the Broncos offense. The Eagles defensive players and Manning remarked how the system has evolved in 2013. Stopping Manning requires many of the same principles as the last decade. But stopping the Broncos offense is different this year.
"It's not much in the scheme that has changed, except his weapons," veteran cornerback Cary Williams said. "He has a legit team."
There's one other element of trying to stop Manning that cannot be lost: the mystique of the quarterback. Kelly said Manning and Tom Brady are the two best quarterbacks he has seen against the blitz. Michael Vick said he's not bothered by all the Manning acclaim, and yearns to play against the ballyhooed players at his position.
But on the field, there cannot be any reverence. Williams, who was on a Ravens team that beat Manning in last season's playoffs, insisted that the Eagles must embrace the matchup.
"If you don't want to play the best, you don't belong here," Williams said. "As a player, as a competitor, I look forward to it. It's an opportunity of a lifetime."
One of the reasons the Eagles signed Williams was to help instill a winning culture in the locker room. When asked what was said in the Ravens locker room before a Manning game, Williams smiled.
"If I can tell you in choice words, I would," Williams said.
The Ravens game plan was similar to McDermott's in 2010. Williams said Baltimore showed different looks so that Manning could not get easy reads. They also did not bite on the pre-snap maneuvering that Manning is known to do. Several players said that if the Eagles adjust too much to what Manning does, then they'll end up confusing themselves.
Asked if it's futile to blitz Manning because he's so effective against the rush, Williams quickly rejected the idea.
"Why not blitz him? What, you're going to play scared?" Williams said.
This is the message from Eagles veterans. If there's a solution for stopping Manning, teams would have used it during the last 16 years. But they cannot fall for what Manning does, and they cannot fear the future Hall of Famer.
"It's about all our 11 guys being on the same page, knowing where to be, and knowing our assignments," Ryans said. "That's how this is done."