Update: Jason Garrett met with the media on Monday and said the team has not made a determination on Romo's status for Week 17.
"He's going to get treatment, we'll see what his status is for Wednesday and this coming week," Garrett said, via Ian Rapoport.
According to Jay Glazer of Fox Sports and Chris Mortensen of ESPN, Romo has a herniated disk in his back. Mortensen reports surgery is necessary while Glazer said Romo is "currently looking at options."
Romo has played through some back pain in recent weeks. After the game against Washington, Romo said he took a hit in the first half that aggravated the injury. He was able to finish the game and was scheduled to undergo a MRI on Monday. It initially appeared to be a minor issue and he said on Sunday he did not think the injury would impact his ability to play this week.
The injury turned out to be more serious than originally thought and will now keep Romo out for the rest of the season. Back issues have been a problem for Romo recently, but he said his most recent injury is not related to the cyst he had removed during the offseason.