IRVING, Texas -- The Dallas Cowboys' running back situation continues to take hits as Felix Jones' health now is an area of concern as the team prepares for its Sunday night showdown against the unbeaten Atlanta Falcons.

The Cowboys already are preparing for a third straight game without DeMarco Murray, who is recovering from a sprained foot.

Jones has been troubled by a bruised knee that kept him out of the final two drives of the Oct. 21 game at Carolina, and he also suffered a nerve irritation in his neck in the first series of that game. He carried the ball 13 times for 19 yards against the New York Giants last week and did not catch a pass.

"I'm concerned because he’s not healthy," Cowboys executive vice president Stephen Jones said Thursday. "We got one already that can't play, and he's banged up. I give Felix a lot of credit. There are other backs that probably just say, 'Hey, I need to get well before I get out there.' But Felix is tough and he wants to be out there and we know he's not 100 percent but he wants to play.

"We’ve had players in the past that wouldn’t go out like that."

Jones was on the practice field Thursday with his knee taped up. He was limited Wednesday and hadn't taken part in a full practice session in two weeks. Phillip Tanner and Lance Dunbar are the two healthy tailbacks on the 53-man roster.

Tanner did not pick up a yard on two carries against the Giants. He has 61 carries on24 carries this season. Dunbar, who started the year on the practice squad, has one carry for 11 yards against Baltimore on Oct. 14.

"We'll see what his health is going into this game," coach Jason Garrett said Thursday. "Certainly those other guys have to be ready to play."