Coach Andy Reid said Monday that Westbrook, who was back in the lineup after sitting out the Week 4 game against Chicago with an ankle injury, broke two ribs on the eighth play of the Eagles' 23-17 loss to the Washington Redskins on Sunday.
"He is very sore," Reid said.
Despite the injury, Westbrook carried the ball 12 times for 33 yards and caught six passes for 51 yards in the game. He leads the Eagles with 194 yards rushing and has six touchdowns, two receiving.
Reid would not speculate about Westbrook's availability for the Eagles' game at San Francisco this weekend.
"We'll see how it works out for him," Reid said.
Westbrook said he was taking a wait-and-see approach, but that Correll Buckhalter should take his place in the backfield if the injury is limiting him too much later in the week.
"Do I want to be out there at 45 percent and not wanting to take a hit and hurting this team more than I'm helping it?" Westbrook asked on his radio show on 950 ESPN. "No. ... I wouldn't want to set the team back like that."
Reid was angry after the Eagles, who were up 14-0 against the Redskins, slipped to 2-3 this season.
"When you are up by 14 points, you expect to finish the thing
off and do the right things and win the game," he said.
"We are all embarrassed by it. We put a lot of time and
effort into it. I don't think you want to go out and have a game
like that," he said.
Information from The Associated Press and Reuters was used in this report.