While Cowboys' officials are not ruling him out of the game, any serious back injury leads to speculation of surgery, something Romo most likely will have and the possibility he won't play.
Newly-signed backup Jon Kitna had a herniated disk problem in 2011, his last season with the Cowboys.
"There are varying levels," Kitna said. "I don't know where his is at. There are varying levels. You can be completely incapacitated. Like mine was something that never went down into the legs. When it gets you, it gets you. There's not much you can do about it."