"I regret that we're not going to have him against Carolina, which looks obvious" Jerry Jones said Tuesday on his weekly radio show. "I'm encouraged we're going to have him as we move along. He's playing outstanding."
The Cowboys have determined that Murray will not require surgery, a source told ESPN NFL Insider Ed Werder. He is wearing a protective boot and using crutches. Murray's availability will be determined on a week-to-week basis.
An MRI, taken Monday, revealed ligament damage but no broken bones for Murray, who suffered the injury in the first half of Sunday's 31-29 loss to the Baltimore Ravens.
In addition, an MRI on the right shoulder of cornerback Mike Jenkins came back negative and he will be available to play against Carolina, sources told ESPN NFL Insider Adam Schefter.
Murray, who had his rookie season cut short last year when he fractured his ankle in a game against the New York Giants, rushed for 90 yards Sunday before leaving in the first half with the injury. He had one third-quarter carry for 3 yards but was kept out of the rest of the game.
After the game, Murray said he wanted to return, and he was not in a walking boot.
If Murray misses an extended amount of time, the Cowboys would turn to Felix Jones. He picked up 92 yards on 18 carries against Baltimore but missed time in the second half to get intravenous fluids because he was cramping.
It is possible the Cowboys could look for more veteran running back help if Murray is out. Last year they signed Sammy Morris with four games to play because Murray hurt his ankle and Tanner was on injured reserve with a hamstring injury.
This could be Jones' last, best chance to show he can be an every-down running back before he hits free agency after the season.
He failed the conditioning test to open training camp and had a woeful preseason that carried over into the regular season. Prior to Sunday's game, he had 13 yards on three carries in the first four games.
Meanwhile, Jenkins left Sunday's loss to the Ravens early in the second quarter after attempting to tackle Ray Rice on a 43-yard catch and run. Jenkins returned in the third quarter and finished the game.
After playing hurt most of last season, Jenkins sought a long-term extension from the Cowboys heading into the final year of his rookie deal. Instead, Jenkins lost his starting job after the Cowboys signed Brandon Carr and drafted Morris Claiborne in the first round. Much of Jenkins' playing time this season has come as a safety/corner hybrid in the Cowboys' dime package.
In other injury news, defensive end Sean Lissemore will miss a few weeks with a high right ankle sprain suffered in the first quarter of Sunday's loss at Baltimore.
"I want to get back as soon as possible, whatever that takes," Lissemore said. "But I don't want to come back too soon and set myself back. As soon as I can get back, I will."
Nose tackle Jay Ratliff missed six weeks (four games) with a high ankle sprain injury suffered in the preseason and finally made his season debut Sunday against the Ravens. Marcus Spears will replace Lissemore in the defensive line rotation.
Claiborne had an MRI Monday on his left knee but he was able to return to the Ravens' game.
ESPN NFL Insider Adam Schefter and ESPNDallas.com's Tim MacMahon contributed to this report.