On Sunday, Philadelphia (1-2), ranked 30th in total defense, will meet the NFL's top-ranked offense in the Denver Broncos (3-0).
The Broncos scored 49, 41 and 37 points in three relatively easy wins over Baltimore, the New York Giants, and Oakland, and quarterback Peyton Manning has a rating of 134.7.
At the same time, the Eagles have allowed 27, 33 and 26 points to Washington, San Diego and Kansas City.
"Usually you have a main guy as part of an offense, a star that you can load up and take him away," Eagles defensive coordinator Bill Davis said. "Peyton makes you defend the field. He has all his guys there. There's a bunch of high-quality, skill position players. He distributes it equally. There's not one person he favors."
Manning has used 10 different receivers this season and has touchdown passes to five of them.
It's nothing new to Davis. He remembers the last time he faced Manning. As defensive coordinator in Arizona, Davis and the Cardinals met the Indianapolis Colts.
"We held him to seven points in the first half," Davis said. "We felt good about what we were doing. He figured us out. It ended up being 31-13. We lost.
"I guess you can never relax against Peyton. He is constantly grinding on, figuring out what you're doing."
The Eagles have two options. Blitz like crazy, or drop eight into coverage and try to take away the receivers.
"The one thing with Peyton that you realize is that you can't just do one thing against him," Eagles coach Chip Kelly said. "He's such a great mind. You may blitz him, but if you beat him the first time on the blitz, he's going to come back and beat you on the blitz the next time. You have to try to give him different looks. But you have to make sure your disguise isn't a liability.
"It's very difficult when you see your quarterback playing at that level right now. He's got a lot of weapons and he uses them. It's a tough challenge for us this week."
For an Eagles defense that has allowed an opposing quarterback rating of 96.9, that challenge might even be more difficult with veteran safety Patrick Chung out of practice. Chung, one of the Eagles' key free-agent additions this offseason, injured his shoulder in last Thursday night's loss to Kansas City.
Rookie Earl Wolff has worked with the starters this week. Through the first three games, Wolff has split time with Nate Allen at one safety spot. Now, they're both starting.
"We'll see how it goes over the next few days. Right now, he's not ready to come back," Kelly said of Chung. "Earl, I think he's growing. He came in here as a rookie and is starting to play a little more as he goes through. There's been improvement.
Wolff hasn't seen anything like the Broncos' offense, which is averaging 486.7 yards per game, 374.7 through the air.
"They have a very good offense, no doubt," Eagles linebacker Trent Cole said. "We know what we have to do and we're going to be ready. We have to play our game. We have to be sound.
"We can't make any mistakes and we'll be all right."
AP NFL website: http://www.pro32.ap.org