The Eagles could be missing their star running back for the second time in three weeks Sunday when they visit the San Francisco 49ers in hopes of avoiding a third straight defeat and an even bigger deficit in the loaded NFC East.

Westbrook returned from a one-game absence due to an ankle injury last Sunday, finishing with 33 yards and a touchdown on 12 carries and six catches for 51 yards in Philadelphia's 23-17 home loss to Washington. He played the entire game despite breaking two ribs, which could sideline him this week.

"I am just trying to get healthy enough to play and get to the point where the pain is not as strong and try to get out there on the field," Westbrook said Wednesday after missing practice again.

"It's tough to get sleep. When you have broken ribs and you sneeze, turn, twist, make a sudden move, it's sore."

Westbrook led the NFL with 2,104 scrimmage yards in 15 games in 2007 and is tied for the league lead this season with six total touchdowns despite missing the Eagles' Week 4 loss at Chicago.

"It's definitely frustrating," Westbrook said. "You try to go out there, you want to be as healthy as possible and produce for your team. When you're out there and you keep getting injured and keep getting nicked up, it's tough to handle that type of thing."

If Westbrook can't play, the Eagles (2-3) could have a hard time bouncing back from consecutive disheartening defeats that derailed their strong start.

Philadelphia opened the season with a dominating 38-3 victory over St. Louis before falling short in a 41-37 loss at Dallas in a matchup of NFC East favorites in Week 2. The Eagles got back on track as their defense carried them to a 15-6 victory over Pittsburgh in Week 3, but have lost their last two to Chicago and Washington by a combined 10 points.

"I was embarrassed these last two weeks," quarterback Donovan McNabb said Sunday after Philadelphia blew a 14-0 lead by getting outscored 23-3 in the last three quarters. "I mean, to two teams we shouldn't have lost to. When you make mistakes and you don't capitalize on opportunities, things like this happen. ... You find yourself here wondering why."

The Eagles have scored 38 points in the second halves of their first five games, compared to 89 points before halftime. They've totaled only nine second-half points in their last two games.

Those recent struggles have put the Eagles in an early hole in the NFC East, widely considered the league's best division. They're in last place with two fewer wins than each of their division rivals.

"It's going to be tough for us, but we're going to continue to fight," Westbrook said. "We're not going to quit."

The 49ers (2-3) were making similar statements after they were held to a season-low 199 total yards and outscored 23-7 in the final three quarters of their 30-21 loss to New England last Sunday.

"We've just got to play as one," said running back Frank Gore, who had 54 yards on 12 carries and caught a touchdown pass. "We've got a lot of great talent in here, but we've just got to get over the hump."

San Francisco committed three turnovers last week and has totaled 11 in three losses, compared to one in two wins.

An inconsistent J.T. O'Sullivan is one reason the Niners have lost their last two games. The first-year starter has completed less than half of his pass attempts in that span while throwing five interceptions.

Though the 49ers missed a chance to get a signature win over a high-profile team like New England, they'll get another chance to prove their mettle against the Eagles, who are still considered an NFC contender.

"I think we lost a game that we should have won today, (and) I think everybody feels like that," defensive lineman Justin Smith said last Sunday. "We have to get back and learn from it. It's not the end of the world. We're 2-3. We need to come out and get a win next week."

San Francisco has lost its last two games against Philadelphia by a combined 53 points. McNabb passed for 296 yards and two touchdowns, and Westbrook ran for 117 and two scores in the Eagles' 38-24 victory the last time the teams met Sept. 24, 2006.