Benson to miss 3-6 weeks with sprained MCL

In a classic good-news/bad-news scenario, Chicago Bears rookie tailback Cedric Benson suffered no serious structural damage to his right knee Sunday, but the team's first-round draft choice is expected to miss 3-6 weeks with a sprained medial collateral ligament.

Benson was injured in the second quarter of Sunday's victory over San Francisco when his right knee buckled, then bent under him at a grotesque angle. Trainers immediately signaled for a cart to remove Benson from the field, he did not return, and he left Soldier Field on Sunday night with an immobilizer on his leg.

"It looked a lot worse than it was," coach Lovie Smith said Monday. "I'll
say that. ... We think right now it's week to week. Hopefully we'll
get him back before long. We don't know exactly how long it will
be, but we know that we'll get him back some time this year."

A Monday morning MRI exam confirmed the sprained MCL, but also indicated that there was no serious structural damage to other ligaments or to the cartilage. Benson will begin treatment immediately with hopes of returning for the final few games of the season.

"We definitely think he [Benson] can be part of the stretch
run," Smith said. "That's why when you see an injury like that,
you are expecting the worst and you find out it's not that bad.

"We need all of our guys and Cedric is a part of what we are
trying to do running the football. Other guys have to pick up the
slack until he gets back."

The injury occurred as Benson, the fourth overall choice in the 2005 draft, was making his first regular-season start, and as Smith had planned to increase his playing time. He carried 12 times for 50 yards against the 49ers before the injury. In eight games, playing primarily as the backup to Thomas Jones, the former University of Texas star has rushed 58 times for 237 yards.

With the injury to Benson, fourth-year veteran Adrian Peterson will assume the No. 2 role behind Jones, who missed Sunday's game with bruised ribs, but is expected to return to the lineup next weekend, when Chicago hosts Carolina. Peterson carried 24 times for 120 yards against the 49ers, both career highs, in an impressive relief appearance.

"Cedric Benson was having a real good game yesterday before he
went down with the injury. Each time he plays we get a chance to
see more and more what he'll be some day for us," Smith said.
"And Adrian Peterson just continues to play well every time we
give him an opportunity."

The Bears, who have won five straight games, statistically rank fifth in the league in rushing offense, and are averaging 135.3 yards per game. On Sunday, they will face a Panthers team that has won six straight games and whose defense, while still allowing a bit more rushing yardage than coach John Fox would prefer, is performing well.

The return of Jones to the lineup means the Bears, who lead the NFC North with a 6-3 record, will have their offensive centerpiece back for the big game. Jones has carried 167 times for 753 yards and six touchdowns.

Len Pasquarelli is a senior NFL writer for ESPN.com. Information from the Associated Press was also used in this report. To check out Len's chat archive, click hereInsider.