Mark Sanchez will eventually be the Dallas Cowboys' backup to Dak Prescott while Tony Romo is out with a compression fracture in his back.

Sanchez agreed to a one-year deal, a source told ESPN’s Adam Schefter, a few days after the Denver Broncos attempted to trade him to the Cowboys.

The Cowboys felt like they had to do something behind Prescott, who will become just the fourth rookie in franchise history to start a season opener, the story said.

Dallas Cowboys quarterback Tony Romo is wearing a back brace as he begins his recovery from a compression fracture of his L1 vertebra that he suffered Thursday against the Seattle Seahawks.

The Dallas Cowboys went 1-11 without quarterback Tony Romo last season, and they may have to turn to rookie Dak Prescott early on this season.

For now, Romo's rehab will consist of rest and immobility, but Garrett will not rule him out of the Sept. 11 season opener against the New York Giants. A source said Romo will miss 6-10 weeks.

"We've gotten a lot of different timetables for when he can return," Garrett said. "We also know that he's played with a broken bone in his back before, so there's no reason for me to stand up here and put a timetable on this. I think a lot of other people outside of this building have suggested they know what the timetable is. That's not the world we live in. We live in the world day by day, do what you can to get yourself better and we'll update you as we go."

Dak Prescott took the first-team reps on Sunday with Jameill Showers the backup. The Cowboys are expected to look for a veteran backup while Romo is out.

The Cowboys have opted not to make an addition to their quarterback group following Kellen Moore’s broken ankle with owner Jerry Jones saying that fourth-round pick Dak Prescott has done enough in practice to get an opportunity to serve as Tony Romo’s backup this season.

Prescott’s performance in Saturday night’s preseason opener in Los Angeles is unlikely to lead the team to rethink that plan. Prescott completed 10-of-12 passes for 139 yards and two touchdowns with the two incompletions coming on drops by tight end Geoff Swaim. Two of the completions went to Dez Bryant, including a 10-yard touchdown, and the veteran receiver said that Prescott didn’t look like he was playing his first NFL game.

“I think the best thing about Dak is that he is extremely calm,” Bryant said, via the Fort Worth Star-Telegram. “It’s like he’s been here before. He’s not playing like a rookie. He is going to be very good; he’s special.”

The Dallas backup QB job is one to pay attention to given Romo's age and injury history. Should Romo get hurt again, the team's QB2 could have some fantasy value with a talent offense around him and a very good offensive line.

The Dallas Cowboys are considering the Nick Foles option but also discussing potential trades in response to losing backup quarterback Kellen Moore to a right leg fracture, a league source told ESPN's Ed Werder on Wednesday.

Foles bought his way out of his Los Angeles Rams contract last week and is an unrestricted free agent. The Cowboys discussed with the Rams their interest in trading for him but then drafted quarterback Dak Prescott.

The Cowboys have Wednesday off but probably need to add a quarterback quickly if they plan to continue giving starter Tony Romo every third day off.