"You try to show him different things, give him different looks,'' Eagles cornerback Cary Williams said. "Not give him an easy read on a lot of things. He's going to come up there [to the line of scrimmage] and do his show and try to get you to show what you're doing.
"The thing is, you have to try and stay as calm as possible during those situations and not give him anything. He can look at your stance. He can look at your eyes and tell if you're coming [on a blitz]. He's been around the game for so long, man, he's mastered all of those things.''
Ready or not, here he comes Sunday. Fresh off a 374-yard, three-touchdown performance against the Raiders, which followed a 307-yard, two-touchdown performance against the Giants, which followed a 462-yard, seven-touchdown Week 1 performance against the defending Super Bowl-champion Ravens, Manning will take aim at an Eagles defense that is ranked 30th in total defense, 29th against the pass and 26th in points allowed.
This doesn't even seem fair, but as someone once said, that's why they play the game.
"Football doesn't change just because of Peyton Manning,'' Eagles cornerback Brandon Boykin said. "I know a lot of people are saying how great of a quarterback he is, and he is.
"But at the same time, he's not perfect. He's made mistakes. They're few and far between, and people almost think it's impossible to stop him. But as a defense, we are looking at those things he does wrong, looking at the things we can be effective at.''
At the moment, the 37-year-old Manning is playing as close to perfect as he has in his career. He's first in the league in passing with a 134.7 rating. He's first in completion percentage (.730) and first in yards per attempt (9.37).
He's the first quarterback in league history to throw 12 touchdown passes in the first three games of a season and he still hasn't thrown an interception.
"He's the best,'' safety Nate Allen said. "He's looking guys off. Putting safeties right where he wants them. Then he goes back the other way. That's why we've got to be disciplined. Stay in our zone and be smart against him. Because he's the top of the line. He's the man.''
He is not unbeatable. Williams was with the Ravens last year when they took down Manning and the Broncos in overtime in the playoffs. The Ravens intercepted him twice. Held him to 6.7 yards per attempt.
Linebacker Connor Barwin was with the Texans last year when they beat the Broncos in Week 3, 31-25. Manning completed just 26 of 52 passes in that game and averaged just 6.3 yards per attempt.
So what's the secret formula for beating Manning?
"The formula against Peyton isn't really different than against anybody else,'' Barwin said. "And you shouldn't try to make it different. You get guys on receivers and you get pressure on him. That's how you beat him.
"He's obviously better than most at getting the ball out and finding the right guy. But that doesn't change what you do. You've just got to do what you're supposed to do. [Last year], we made a couple of plays on the balls he threw. That's how we beat him. There's no secret.''
One thing you probably won't see the Eagles do much of against Manning is blitz. Blitzing Manning is like throwing empty beer cans at Superman.
"Probably him and Tom Brady are the two best I've ever seen [against the blitz],'' Eagles coach Chip Kelly said. "You're talking about two of the all-time greats.''
Since 2008, Manning has a sick 101.9 passer rating against the blitz, according to data by Pro Football Focus. That includes a 66.7 completion rate, 40 touchdowns and just 13 interceptions.
In the Broncos' first three games, Manning has an even better passer rating against the blitz - 140.7 - than his overall passer rating.
That said, the Ravens didn't blitz Manning a lot in their playoff win over the Broncos last January. But when they did, it was effective. He was just 5-for-10 for 48 yards against the Ravens' blitz.
In the loss to Barwin and the Texans earlier in the season, Manning was just 6-for-15 for 73 yards when Houston sent five or more rushers.
"Why not blitz him?'' Williams said. "What, you gonna play scared? He's a man. He's a great player. But we've got to do what we've been doing. Just get better at it. Play with better technique. Tackle.''
In their first two games, the Eagles blitzed the hell out of the Redskins' Robert Griffin III and the Chargers' Philip Rivers. It worked against the rusty Griffin, who completed just eight of 21 passes and threw an interception against the blitz. It didn't work against Rivers, who was 21-for-27 for 220 yards and two touchdowns when the Eagles blitzed him.
Last week against the Chiefs, the Eagles only sent five or more rushers after Alex Smith on five of his 46 dropbacks. Rushed him with four defenders on 38 of those 46 dropbacks. That likely will be their approach Sunday.
"We have to apply pressure on him,'' linebacker Trent Cole said. "Get on top of him fast.''
Three years ago, the Eagles defeated Manning and the Colts, 26-24. Sacked him three times, intercepted him twice and held him to 5.8 yards per attempt.
"I remember we were getting back there and we were hitting him,'' Cole said. "You can get on him if you just disguise some things and apply that pressure and get after him.''
Then something came to him.
"I remember now,'' he said. "We did something to distract him that day. I'm going to go tell my coach what it was.''
In the loss to the Chiefs last week, the defense played much better than it did the week before against the Chargers. It sacked Smith five times. It didn't allow a touchdown pass.
They're not going to sack Manning five times. But they need to make him uncomfortable.
"You've got to get pressure on him,'' Boykin said. "Even when you do have pressure on him, he gets the ball out so quick. That's why everybody has to be on the same page.
"The key is going to be tackling. When he gets the ball out quickly, you won't be in that tight coverage you necessarily want to be in. So you have to make those tackles.''
On Twitter: @Pdomo