Westbrook broke two ribs in the Eagles' 23-17 loss to Washington last Sunday, though he kept playing and finished the game. He sat out a 24-20 loss at Chicago on Sept. 28 because of an ankle injury.
Two-time Pro Bowl guard Shawn Andrews (back) and wide receiver Reggie Brown (groin) also won't play. Wideout Kevin Curtis is expected to see his first action this season after having surgery for a sports hernia.
"Brian wants to go. He's in the mind-set that he wants to play, but it's a decision that I've got to make," coach Andy Reid said Friday. "He's a tough nut and I know that. I've got to do what I think is best for him and the football team down the road. It made the decision a little easier for me than it is for him. Obviously, he wants to contribute and compete."
Westbrook leads the Eagles (2-3) with 194 yards rushing and has six touchdowns, two receiving. He should return on Oct. 26 after a bye week.
"I think the bye week will help him," Reid said. "I think it will take some of the sting out of that thing. If he were to get hit on it this week, it would slow down the process of healing."