If there was not enough theater for Sunday's game between the Eagles and Cowboys to determine the NFC East title, the plot took a turn Monday when the news broke that Dallas quarterback Tony Romo would miss the remainder of the season, according to an ESPN report.

Cowboys coach Jason Garrett told reporters that Romo was getting treatment on his back and that no determination had been made on his status.

Romo's backup is Kyle Orton, who could be standing between the Eagles and a playoff berth.

"Kyle's had success in this league," Eagles general manager Howie Roseman said on his radio show on WIP-FM (94.1). "We've played backup quarterbacks who've had success against us. We've got to keep our edge on. This is too big a game or a situation to take anyone lightly."

Earlier in the day, Eagles coach Chip Kelly called Romo "as talented a quarterback as there is in this league." The news likely required the Eagles to make an afternoon adjustment in preparations to study Orton, who has thrown only 15 regular-season passes in the last two years. Orton, 31, is 1-1 in his career against the Eagles, with six touchdowns and three interceptions.

The news complicated a rematch of the Eagles' 17-3 loss to the Cowboys on Oct. 20. A day after that game, Kelly said that he did not think there was a big difference between the Eagles and the Cowboys.

That thought came when Nick Foles was struggling and Romo was healthy. In the two months since, the Eagles have won six of eight games and watched Foles blossom into one of the NFL's most productive quarterbacks. They also have taken over first place in the NFC East.

Kelly said he turned his attention to the Cowboys game immediately after Sunday's 54-11 win over the Chicago Bears.

If the Eagles win or tie on Sunday, they will clinch the NFC East title and a playoff bid. A loss will send the Cowboys to the postseason.

"It's very black-and-white," Kelly said Monday. "I don't think I have to hammer that home that this is the biggest game, because it is."

Kelly has coached in big games before, including the 2011 national championship. He said it's important that the Eagles maintain a consistent approach to avoid "living in peaks and valleys."

Kelly might not have been in a valley on the day after the October loss to Dallas, but the team's fans were. The worst performance of Foles' two-year career ended after he suffered a third-quarter concussion. He finished 11 of 29 for 80 yards. Kelly's play-calling did not muster a single touchdown.

There are no questions about Kelly's offense now. After a two-game stretch without an offensive touchdown, the Eagles' attack has averaged more than four TDs per game. The defense has allowed more than 21 points just once since the loss to Dallas. Kelly is confident that the Eagles are a different team than the one the Cowboys beat in October.

"We're just more experienced. We've been together longer," Kelly said. "I think we have a better understanding as a coaching staff of our players and what they can do and putting those guys in a position to make plays. I think everybody is a by-product of their experiences and I think . . . people [are] getting comfortable, understanding the situation and knowing when guys are going right, guys are going left."

The biggest change in the Eagles has been at quarterback. They played three quarterbacks during a two-week span in midseason. Foles has been healthy ever since his return on Nov. 3, providing stability.

"When you have a guy and you can get settled at it, I think it helps because people kind of know where he's going to be and when the ball is going to be released, kind of what his makeup is, and where are we going to be as an offense," Kelly said. "That's been a huge part of our success over these last couple of games."

But the Eagles have seen how fortunes can quickly change. They had a five-game winning streak snapped by a three-win Vikings team with five starters missing because of injuries.

The Cowboys now stand in the way - likely without Romo - and the Eagles must ensure that they maintain their edge if they want to win the NFC East.

"This league will test you," Kelly said. "It's not what you did last week, it's what you do this week."