Olandis Gary draws a crowd Monday when he rushes for 80 yards on 13 carries.(AP)

Even the tailback himself is not certain when the injury occurred, and there are conflicting reports from the team and sources close to Gary. Those sources told SportsLine.com that Gary had some pain in the knee during the preseason schedule, but continued to play with it. The Broncos think Gary injured the knee in the third quarter of Monday's loss at St. Louis.

At one point in the third quarter, Gary went to the sideline and pulled an elastic sleeve over the knee. But he returned to the game and carried three times in the fourth quarter for 39 yards. He also was the intended receiver on an incomplete pass and was on the field for the Broncos' final series. His fourth-quarter rushes were for 25, 13 and 1 yard.

In all, Gary carried 13 times for 80 yards and had three catches for 10 yards. He entered the game early in the second quarter when starter Terrell Davis exited with a sprained ankle. The status of Davis, who had to be taken to the team bus on a cart, remains uncertain for this week's game with the Atlanta Falcons.

Davis, who is coming off an anterior cruciate injury that sidelined him for 12 games in 1999, insisted after the Monday game he will play this week.

A former University of Georgia standout, Gary replaced Davis, another onetime Bulldogs star, as the starter in 1999. He rushed for a team-high 1,159 yards and seven touchdowns on 276 carries.

Coach Mike Shanahan planned to lessen the workload for Davis this season by using Gary for several series every game.

The Rams also lost a key performer to a Monday night knee injury, but not one with the severity of Gary's torn ACL. SportstLine.com confirmed defensive tackle D'Marco Farr suffered a torn knee cartilage late in the game that will sideline him for about a month.