Update: Tuesday, 10:08 a.m.
A back injury will keep Tony Romo out for Sunday's prime-time, division-deciding game between the Eagles and Cowboys, according to ESPN's Adam Schefter. Romo has a herniated disc that will require surgery, according to Chris Mortensen.
However, Cowboys head coach Jason Garrett did not confirm the report Monday afternoon, instead saying that Romo would "continue to be evaluated." When asked if Romo was out for the season, he responded that the Cowboys have not "made that determination at all." Garrett did acknowledge that Dallas will add a quarterback to its 53-man roster.
According to Pro Football Talk, Romo wants to play with the herniated disc "but most likely can't."
Schefter also reports that the Cowboys are scheduled to work out free-agent quarterbacks John Skelton and David Carr on Tuesday. Also, according to multiple reports, Dallas has invited Tyler Thigpen to work out this week.
Romo told reporters that his back had been an issue heading into the Washington game in Week 16 -- which Dallas won 24-23 on a game-winning TD pass to DeMarco Murray with 68 seconds left -- and that the injury was aggravated after a first-half hit.
Romo missed spring OTAs after having a cyst removed from his back in April.
Romo's backup is veteran Kyle Orton, the former quarterback of the Bears, Broncos and Chiefs.
Orton is 3 for 5 passing for 40 yards this season. For his career, he's completed 58.4 percent of his passes for 81 touchdowns, 57 interceptions and a 79.7 QB rating.
Orton has not started a game since 2011 but is 1-1 career against the Eagles.
In 2008 with Chicago, he completed 18 of 34 passes for 199 yards with three touchdowns and two interceptions as the Bears beat the Eagles, 24-20. The following season with Denver, he completed 27 of 41 passes for 189 yards with three touchdowns and one interception in a 30-27 Eagles victory.
Romo has missed just 13 games since becoming the Cowboys' starter in 2006, including 10 in 2010 when he suffered a broken collarbone. Dallas is 6-7 in those contests.
The Cowboys could also be without the quarterback of their defense, middle linebacker Sean Lee. The Penn State product has a sprained neck, hasn't been medically cleared and is doubtful to play Sunday, according to ESPN Dallas.