ST. LOUIS -- Marshall Faulk's recent struggles are due to a bruised left knee that will keep him out of Rams practices this week. He'll also likely miss Sunday's game against the 49ers after being downgraded from probable to questionable on Thursday.
A gimpy Faulk has 20 carries for only 13 yards the last two weeks. First-round pick Steven Jackson almost certainly will start in his place on Sunday against the San Francisco 49ers, and coach Mike Martz said Thursday that Jackson probably should have played more the last two games.
"He's going to carry the load this week," Martz said. "We've got to give Marshall a chance to recover."
Until now, the Rams have made no mention of Faulk's injury. Last year, Faulk had two operations on his right knee. The injury could date to the second week of the season against the Falcons, when he took a blow to the knee.
"He's very quiet about it and doesn't say anything about it and doesn't want anybody to know about it," Martz said. "But nonetheless, we need to do the right thing by Marshall.
"He'll be involved with the game plan and if he feels like he's ready to go on Sunday, great, great."
Another sign that Faulk probably won't play is third-string back Arlen Harris got some reps in practice Thursday.
Faulk has 161 carries for 683 yards, a 4.2-yard average with three touchdowns. Jackson, the first running back selected in the draft, has 377 yards on 74 carries, a 5.1-yard average, and two touchdowns.
Martz said he's seen significant progress in Jackson in recent weeks. Unlike the slippery Faulk, the 240-pound Jackson is more of a power runner.
"He has complete knowledge, and I guess his background is complete in terms of the trust factor of what you do and what you don't do," Martz said. "He's absolutely prepared, there's no question about it."
Faulk, 31, is in his 11th NFL season and hasn't had a 1,000-yard rushing season since 2001. Martz said he's aware of the need to prepare for a transition.
"He's very aware of his body, and he's aware of Steven's ability," Martz said. "He understands how important it is in order to make it through the season in one piece.
"This is a good setup for him and ultimately it can help him prolong his career."
Both players started Monday's game at Green Bay. Jackson was in the backfield and Faulk was in motion as a receiver.
"It all depends on Marshall's well-being," Martz said. "If he's completely healthy and ready to go we'll stay with our rotation. It's been pretty effective."
Faulk needs 132 yards receiving to pass Larry Centers (6,691) for most in NFL history by a running back. He needs 104 yards rushing to become the 12th player in league history with 12,000.
If Faulk doesn't play Sunday, an impressive streak will end. He's caught a pass in 157 consecutive games, first among active players and fifth best in NFL history.