The Cowboys offense suffered a heavy blow in the first quarter of Sunday's game against the New York Giants when breakout rookie running back DeMarco Murray suffered a fractured right ankle and high ankle sprain.
The injury almost certainly will knock out Murray for the remainder of the regular season, and could end his brilliant rookie campaign entirely.
"It was reported he had a fracture and it appears like he is gone for the season," head coach Jason Garrett said.
With only one other running back on the active roster, Felix Jones, the Cowboys will need to free up a spot to sign another option, and could create room by placing Murray on the injured reserve.
On the Cowboys' second drive of Sunday's inter-division game, Murray carried for eight yards around right end, but his lower leg was caught underneath the tackle by New York defensive end Dave Tollefson. He needed the help of two athletic trainers to get off the field, and was taken into the locker room for further observation.
In his first year out of Oklahoma, the Cowboys' third-round pick had rushed for 897 yards on 164 carries, an average of 5.5 yards per rush. Murray became the Cowboys' starter after team-record 253 yards on the ground against St. Louis in Week 7.
"DeMarco has been a big part of this offense and big part of this football team," quarterback Tony Romo said. "We are lucky to have a guy like Felix, obviously, who can step in."
He was on pace to become the first Cowboys back to surpass 1,000 yards since Julius Jones in 2005.