Dallas Cowboys offensive coordinator Bill Callahan has said that the team will not have to change their offense if Kyle Orton plays this weekend.

Starting quarterback Tony Romo is struggling with a herniated disc in his back, which could see Orton make his first start of the year.

Callahan told the team's official website: "I think he's done a fantastic job with his preparation. Leading up to this point, I think he's done tremendous, so I think it's seamless in terms of transition and what he's done.

"We're going to keep doing what we're doing. I think they like certain plays, certain personnel groupings and certain concepts more than others, I think it's just kind of a personal affinity to what they want. The system doesn't vary that much, though.

"He has good experience. He has knowledge of the game. He's been through issues and problems, and he knows how to solve them. He knows what they are, and they're recognisable to him. That's why we have that opportunity to have a veteran quarterback as a backup. We're very fortunate in that respect."

The Cowboys face the Philadelphia Eagles for a place in the NFL playoffs on Sunday.