FRISCO -- Tony Romo's comeback has encountered an unexpected delay that clouds this season and his future.

The fallout leaves the immediate fate of the Cowboys in the hands of a rookie quarterback club officials hoped would not see the field this season.

Romo won't play in the season opener in two weeks after an MRI revealed he fractured a vertebra in his lower back during the team's preseason loss to Seattle. Sources said the quarterback suffered an L1 compression fracture that will keep him out from six to 10 weeks but will not require surgery.

Owner Jerry Jones describes the injury as "a significant setback'' but stressed he's comfortable opening the season with Dak Prescott. The Mississippi State star was taken in the fourth round of the April draft as a young quarterback to develop for the future, something the Cowboys have failed to do during Romo's tenure. The expectation was to carry Prescott on the roster as the No. 3 quarterback in 2016.

But injuries to Romo and backup Kellen Moore (fractured ankle) have thrust him into the spotlight well ahead of that timetable. Prescott has responded with a phenomenal preseason performance, completing 39-of-50 passes for 454 yards with five touchdowns and no interceptions. He's carried the ball seven times for another 53 yards and two touchdowns.

"Dak has certainly, without question, created tangible energy on our team during training camp,'' Jones said. "Him going out and making some plays in the ballgame is just the tip of the iceberg.

"It's his preparation. It's how he carries himself, everything, the whole effort it takes to make a quarterback in the NFL. The quality of his preparation is a real comforting thought here.

"We're early in this thought process as to totally how we'll respond, but not as to whether or not he's a starter.''

This startling twist is the result of a blow Romo took in Thursday night's loss to Seattle. On the third play of the game, Romo took off and went into a slide as Seahawks linebacker Cliff Avril came over the top. It appeared to be a rather innocuous play, the kind that happens numerous times in every NFL game.

Romo didn't return to the game. But afterwards the quarterback said he felt fine, there was no need for an X-ray or MRI and added that he felt like he dodged a bullet.

He didn't. The back didn't feel right Friday so Romo underwent an MRI which revealed the fracture.

The injury undercuts what Romo has called one of his strongest offseasons in recent years. The quarterback missed a career-high 12 games last season after he fractured his clavicle twice.

"He will come back,'' Jones said. "This is nowhere near the issue he had last year (clavicle), not even in the same league as far as we're concerned.''

This is the fourth significant back injury Romo's endured in the last three years. He had a cyst removed in the spring of 2013 and missed the team's offseason program. Before the year was done, he underwent surgery for a herniated disk, missing the final game of the regular season against Philadelphia when the team had a chance to win the division.

In November of '14 he missed a game after suffering a fracture of the transverse process in his back.

Romo is 36-years-old. The frequency of these injuries, while unrelated, casts doubt on how much longer he'll be able to play. Executive vice president Stephen Jones conceded that's a fair question, one he's said Romo himself has contemplated.

But there is no talk of retirement at this moment.

Jerry Jones was watching his grandson, John Stephen Jones, open the season for Highland Park as its starting quarterback when he was informed of Romo's injury. The owner has had several conversations with Romo since learning of the MRI results and said in each the quarterback expressed his commitment to return this season.

"Just as you would expect from him, the competitive nature to get back and his concern for the team,'' Jerry Jones said. "There was disappointment, but he had a very genuine positiveness about the nature of the injury as to how it relates to his back in general.

"The first thing he and everyone medically said it's apart from anything else that's happened to his back. When it's healed, it won't impact the others. He said, 'look, this is not something that is a long term issue for me. It's not like it's age or wear and tear.' ''

The Cowboys have another week to determine whether or not to place Romo on the injured list to open the season. If that happens, and it's the most likely scenario at the moment, the soonest he would be eligible to return would be Oct. 30 against Philadelphia.

"We've got to make a decision what is the best course of action for us, whether designated to return or not,'' Stephen Jones said. "We'll see.''

Prescott, meanwhile, finds himself in a position that hasn't been kind to his predecessors. Since Romo became the Cowboys starting quarterback during the '06 season the team is 7-20 in games in which he hasn't played.

Stephen Jones points to the team's offensive line, which he calls arguably the best in the league, along with receiver Dez Bryant, tight end Jason Witten, rookie running back Ezekiel Elliott and others as the offensive support that can help Prescott succeed. He stressed the importance of the rookie quarterback not turning the ball over or trying to do too much.

"I think it's the best option we have,'' Stephen Jones said of Prescott becoming the first rookie to start a game for the Cowboys in 14 years. "We're confident he'll go out there and do a good job with this football team.

"It's a great opportunity for him. He has good energy, a good chemistry with our football team. I just think he's the right answer for us right now.''

Stephen Jones said the club "will certainly discuss'' adding a veteran backup to open the season behind Prescott but indicated the market is thin.

The season, for now, is squarely in the hands of Prescott. Romo's return and future is a conversation for another day.

"It's disappointing,'' Stephen Jones said of the Romo's injury. "But we set the record straight to start training camp. We're going to focus on the guys who are here to win football games.

"The focus will shift to Dak.''

Catch David Moore on The Ticket (KTCK-AM 1310 and 96.7 FM) with The Musers at 9:35 a.m. and The Hardline at 4:10 p .m. every Monday through Friday during the preseason.

Twitter: @DavidMooreDMN

TONY ROMO OUT 6-10 WEEKS: MORE COVERAGE

Cliff Avril knocks Dallas quarterback Tony Romo out of the game with this sack on the third play of the game Thursday. The Dallas Cowboys played the Seattle Seahawks in preseason football Thursday, August 25, 2016 at CenturyLink Field in Seattle. Romo sustained a broken bone in his back when he was hit from behind by Seattles Cliff Avrill and slid awkwardly on the third play of a preseason game. (Dean Rutz/The Seattle Times)

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