That's because, according to NFL Insider Adam Schefter, Romo is done for the season.
Cowboys QB Tony Romo has been ruled out the rest of the season due to his back injury, per league source.
— Adam Schefter (@AdamSchefter) December 23, 2013
Which means it's KYLE ORTON TIME BABY. This also means, in an ironic twist of fate, the Cowboys will win the Super Bowl this year. You can count on it. I hate the Cowboys and would be okay with things going down this way. Because then they'd be stuck starting Romo next year in a bid to repeat.