IRVING, Texas » Tony Romo’s season is over, and the Dallas Cowboys will have to win without their star quarterback in a third straight playoffs-or-bust finale.

Coach Jason Garrett said Romo had back surgery today, and Kyle Orton will start when Dallas faces Philadelphia on Sunday night with the NFC East title and a postseason berth on the line.

Garrett said Romo underwent treatment all week in hopes of playing after injuring his back in a season-saving 24-23 victory against Washington. The winning touchdown came after the injury on Romo’s fourth-down pass to DeMarco Murray in the final 2 minutes.

Romo hurt himself when he tripped over his foot while trying to escape pressure earlier in the fourth quarter.

"He might have had his finest hour against the Redskins last week, what he did at the end of that ballgame under the circumstances," Garrett said. "Pretty special."

Romo lost the past two winner-take-all finales — to the New York Giants two years ago and Washington last season. He also lost to the Eagles in the same situation in 2008 and now will miss a chance to improve his 1-6 record in elimination games.

"He’s devastated," Garrett said. "Devastated. He puts a lot into this."

Philadelphia (9-6) is trying to complete a worst-to-first turnaround from a 4-12 season under first-year coach Chip Kelly. The Cowboys (8-7) want to end a three-year playoff drought and avoid a third 8-8 finish in Garrett’s three full seasons as coach.

Dallas will have to do it without its defensive leader, too.

Linebacker Sean Lee will miss his third straight game with a sprained neck. He’ll wind up sidelined for five of the last six regular-season games. He was out for two with a hamstring injury.

Lee was forced to watch last year’s season-ending loss to the Redskins with a toe injury sustained in the sixth game.

"You have this picture of how the season is going to go and two years in a row, it doesn’t go the right way from a personal standpoint, from a physical standpoint," Lee said. "I’m just trying to stay positive, trying to help out any way I can, but I hate not being on the football field."

Cowboys owner Jerry Jones said on his radio show that the team and Romo hoped an injection would ease the pain enough to allow him to play. But his condition didn’t improve, and Jones said doctors advised it was better not to wait for surgery.

Jones said the hope is that Romo will be ready for offseason practices in May.

Romo missed all the offseason workouts this year after surgery to remove a cyst from his back in April. Garrett and Jones said the latest injury is not related, but wouldn’t be more specific about today’s procedure.

News of the second back surgery comes nine months after Romo signed a six-year, $108 million extension with $55 million guaranteed.

"He played very well coming off the first procedure he had in the spring," Garrett said. "We are completely confident he’s going to rehab and come back 100 percent."

Orton, who declined to talk to reporters today, will make his first start since the finale in 2011, when he finished the season in Kansas City after getting replaced by Tim Tebow in Denver. He’s appeared in three games and thrown just 15 passes in two seasons as Romo’s backup.

"We’ve been operating as if Kyle Orton is going to be our starting quarterback," Garrett said. "At the same time we were trying to do whatever we could to see if we could help Tony and get him back as quickly as possible. We just felt like this was the best course of action."

Notes: DE DeMarcus Ware missed practice because of an elbow injury but told reporters he is playing. He’s listed as questionable. … WR/KR Dwayne Harris and CB Morris Claiborne are set to return from hamstring injuries. Both are probable. Harris missed three of the past four games, and Claiborne missed six of seven. … LB Ernie Sims is doubtful with a groin injury.