The Eagles have struggled defensively in coach Chip Kelly's first season, and it might get worse before it gets better.
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."