IRVING, Texas - For much of the past eight seasons, the Dallas Cowboys' fortunes have risen and all too often fallen on the performance of Tony Romo. While the veteran quarterback has broken most of the storied franchise's passing records, his often spectacular failures at key moments have made him a polarizing figure among the team's fans.

But when the Cowboys meet the Eagles in a winner-take-all showdown for the NFC East title Sunday night in Arlington, Texas, their faithful might not have Tony Romo to kick around anymore.

Citing unidentified sources, reports from ESPN and NFL.com said Romo, who came up limping during Dallas' 24-23 victory at Washington on Sunday, will miss the rest of the season with a herniated disk in his back that will require surgery.

Cowboys coach Jason Garrett refused to confirm those reports at his news conference late yesterday afternoon. Garrett said Romo underwent an MRI exam on his back. Garrett said said his status is day-to-day and no decision has been made regarding his availability for Sunday's game.

"We have not made that determination at all at this point," Garrett said. "Like with any player, the day after a game, you just want to see what the injury is, and we've done that with Tony. We want to get him involved in treatment as quickly as we can, and we started that process.

"He's going to get treatment each day. We'll evaluate it on a day-by-day basis and see what his status is for Wednesday and for this coming week."

Garrett said the injury was unrelated to surgery Romo has last April to remove a cyst in his back that also forced him out of offseason workouts.

Romo seemed to be injured early in the fourth quarter against Washington as he tried to avoid linebacker Rob Jackson and began limping noticeably. Not only did Romo finish the game, he led the Cowboys on a late 87-yard drive for the winning touchdown with 1 minute, 8 seconds left, throwing the scoring pass to DeMarco Murray after a wild scramble.

After the game, Romo said that he was sore, but that the injury was minor, and his performance after the fact left his teammates convinced he would be fine for Dallas' biggest game of the season.

"I didn't realize he was that injured," said tight end Jason Witten, Romo's closest friend on the team. "Obviously, it's a testament to how he plays and what kind of competitor he is.

"A lot of times, you lose sight of that, what Tony is all about, the kind of toughness that he shows day in and day out, not only mentally but physically. You just commend him how he approaches it, just resilient to find a way. He's so good in those situations and kind of put the team on his back."

If Romo is out, Kyle Orton, a 9-year NFL veteran of four teams with 69 career starts - but none since 2011 - would start against the Eagles. Orton started for Denver before he was ousted to make room for Tim Tebow in '11 and landed in Kansas City, where he started the final three games for the 7-9 Chiefs.

Since then, Orton, who has completed 58.4 percent of his passes with 81 touchdowns and 57 interceptions in his career, has thrown a grand total of 15 passes in three brief appearances at Romo's backup, completing 12 for 129 yards and a touchdown. In his only action this season, Orton went 3-for-5 for 40 yards in mopup duty during a lopsided loss at Chicago.

He is 1-1 against the Eagles, winning with Chicago in 2008 and losing with Denver in 2009. He completed 45 passes in 75 attempts, with six touchdown passes and three interceptions.

Garrett expressed confidence in Orton, whom quarterbacks coach Wade Wilson has called the best backup quarterback in the NFL.

"We have Kyle Orton here for a reason," Garrett said. "Kyle knows he has to be ready . . . He plays the quarterback position the way it's supposed to be played. He's very prepared. He's an experienced guy. He throws the football very well. He's smart, he's tough, he's accurate. He understands what you're trying to do on offense. He understands defenses. He knows where the ball needs to go.

"He has a poise and a calmness and a composure about him of a veteran player. He's been there. He's seen this stuff before . . . The next-man-up philosophy is alive and well for us."

But will the next man be enough to carry the Cowboys past the Eagles to the NFC East title that has barely eluded them the past two seasons?

"Obviously, Tony is a big part of everything we try to do as a football team and obviously as an offense," Witten said. "He's been pretty resilient, and I know he'll do everything he can to get back, but just like any position - that one is probably a little bit tougher - but Kyle has played at a high level and had a lot of success in the league so he's somebody we respect."

Cowboys notes

NFL.com also reported linebacker Sean Lee is out of the season with a neck injury. Jason Garrett would not confirm that, either, also calling Lee day-to-day.