That leaves Jason Witten and Farr and the Cowboys aren't going to overwork Witten

DajLeon Farr was a little thrown off by the question of whether he could be able to play Thursday against Oakland even if he had been a Cowboy for only a few hours.

"Yeah, I'm going to have to," Farr said. "That's Marion Barber what they brought me in for."

The Cowboys signed Farr on Tuesday and cut tight end Kevin Brock, who suffered a high ankle sprain on Sunday. Scott Sicko didn't practice because of a concussion and will not play. Martellus Bennett is likely to miss his second straight game with an ankle sprain.

That leaves Jason Witten and Farr and the Cowboys aren't going to overwork Witten.

Farr said his move to the Cowboys is helped by the fact that San Diego runs a similar offense with similar terminology, considering the Jason Garrett-Norv Turner connection.

"As far as the situation, it's far better," Farr said. "There my best Marion Barber thing was probably going to make the practice squad. With the injuries, I feel like I have a better chance of helping the team out in the games."

 With John Phillips gone for the season because of a torn ligament, the Cowboys will depend on No. 2 tight end Martellus Bennett more than ever.

The Cowboys base much of their offense on using multiple tight ends, with Pro Bowler Jason Witten the constant. They ran 290 plays with two tight ends last season. Those plays produced 1,759 yards for an average gain of 6.07 yards. Only Buffalo had more yardage from two-tight-end sets last season, with 2,092 yards on 361 plays. The Bills had an average gain of 5.80 yards with two tight ends.

Phillips filled in as the second tight end on occasion last season, including when Bennett missed two late-season game because of a concussion. That included the memorable win at New Orleans to end the Saints' try for an undefeated season.