St. Louis -- After an inspiring start under new coach Jim Haslett, the St. Louis Rams are back to rock bottom. They're running out of bodies, too.

Offensive tackle Orlando Pace will be sidelined 2-4 weeks with a knee injury sustained in a 35-16 loss at San Francisco that was not nearly as close as the score indicated. Offensive guard Richie Incognito was scheduled for an MRI exam for a strained rotator cuff.

And running back Steven Jackson was already counted out for this week's game against the Chicago Bears after a second opinion agreed with the Rams' diagnosis as a strain.

One position that won't change: quarterback. Haslett decided to stick with Marc Bulger after consulting with staff and reviewing game tape.

Bulger was 33-for-54 for 295 yards and a touchdown with two interceptions on Sunday. He also lost a fumble on a botched center snap.

"I think we have to do what we feel is best for the organization," Haslett said. "If you have somebody that steps in, is he going to step in for the whole time? Or if he goes bad, are you going to replace him and put Marc back in?

"Just talking to all the offensive coaches, they felt that Marc right now still gives us our best chance to win."

Since injuring his thigh on Oct. 14, Jackson had never been ruled out this early for an upcoming game. He didn't even make the trip to San Francisco.

"He has a strain with a little bit of blood in it and it's going to take some time to heal," Haslett said. "He thought that he should take some time off also."

Pace went to seven straight Pro Bowls from 1999-2005, but the last three seasons he's played in only 18 games. Haslett said Pace may be placed on injured reserve, although he wanted to discuss the situation first with the veteran tackle.

Pace was hurt in the first half when 49ers linebacker Takeo Spikes' leg whipped into the knee. The Rams (2-8) already have eight players on IR.