"It's yet to be determined how long or if he will be out very long," Dallas coach Wade Phillips said Tuesday. "It could get well quickly."
An MRI exam taken Tuesday showed Jones hurt his posterior cruciate ligament during the Cowboys' 21-7 victory over the Carolina Panthers on Monday night. As is becoming typical for Jones, he mixed some dazzling runs with questions about his durability.
He gained 94 yards on only eight attempts, including a 40-yarder on his final carry when he was likely already injured. He also gained 20 yards on a reception.
Injuries seem to slow Jones more than defenses. He injured a thigh in the opener and last year, as a rookie, he was limited to six games because of hamstring and toe problems.
Jones' status is especially important because starting running back Marion Barber missed the last game with a strained left thigh. While third-stringer Tashard Choice had 82 yards on 18 carries, the Cowboys would have to bring up a running back from the practice squad just to have two backs suited up against the Broncos should both Jones and Barber sit out.
Phillips said it's way too early to make any of those decisions, holding out hope he could still have all three backs on Sunday.
Barber was close to being ready, but the medical staff decided Sunday it was best if he waited at least another week for his swelling to go down and his strength to increase. Phillips said the injury usually slows players for 10 days to two weeks; seven or eight days just wasn't enough. Instead of standing on the sideline, he was getting treatment during the game Monday night.
"We couldn't take a chance on losing him for a longer period of time," Phillips said. "He was upset and I appreciate that. He'll want to play again this week. Hopefully we won't have to keep him out, but I still don't know the answer to that."
Phillips said Jones probably injured his knee in the first half, but had enough adrenaline to keep going. After cooling off at halftime, he probably felt it more after the long run. He rode a stationary bicycle on the sideline and returned for two more snaps but didn't get the ball, and then was done for the night.
"He tried to go and he couldn't really go during the game, but that was after he sat out for a while," Phillips said. "I don't know what's going to happen. I'll just have to see."
Copyright 2009 by The Associated Press