Multiple reports say Romo will miss between 6-to-10 weeks with the injury that he suffered during Thursday's preseason game against the Seattle Seahawks.
Romo underwent an MRI exam on Friday, which displayed the break. The Dallas Morning News reported that Romo suffered a broken vertebra in his lower back.
Cowboys owner Jerry Jones told the newspaper that surgery isn't necessary and that there's no chance of Romo missing the entire season. Romo has undergone multiple back procedures in the past, including two in 2013.
"He will come back," Jones said. "This is nowhere near the issue he had last year (with the broken clavicle), not even in the same league as far as we're concerned."
Jones and the 36-year-old Romo have had several conversations about the situation and the owner said the quarterback is already itching to return.
"Just as you would expect from him, the competitive nature to get back and his concern for the team," Jones said. "There was disappointment, but he had a very genuine positiveness about the nature of the injury as to how it relates to his back in general.
"The first thing he and everyone medically said it's apart from anything else that's happened to his back. When it's healed, it won't impact the others. He said, "Look, this is not something that is a long term issue for me."
Romo was injured on Dallas' third offensive play on Thursday night. He scrambled from the pocket, then went into a slide near the line of scrimmage. He was crunched by Seahawks defensive end Cliff Avril from the blind side.
After staying on the turf initially, Romo walked off on his own. He threw some passes on the sideline but was held out for the rest of the game by coach Jason Garrett after lobbying to return. Romo completed his lone pass of the game for 11 yards.
"Whenever you take a hit, that was a perfect timed situation," Romo said after the 27-17 loss to the Seahawks. "I was going into a slide. But in a weird way, I feel good about the fact that was probably as tough of a hit I've taken on the back as I've had in the last five years. From that regard, I feel very lucky that it can hold up and I can keep going.
"At the moment when you go down, you crunch so your back gets squished, I guess you could say. You almost feel a sensation as if someone gave you a stinger in your shoulder. It just feels hot for a second. That dissipates after a minute and you're OK. All of those things you felt before with back injuries, those are all fine. Then your strength comes back and you're like OK. It just takes a little bit."
The 36-year-old Romo underwent a pair of back surgeries in 2013 and he missed most of last season with a twice-broken left collarbone. Garrett said the injury is not related to the surgeries Romo had in 2013.
"Again it's not related to the other back issues that he's had (and is) very specific to the hit he took the other night at the game," Garrett said. "And he came out and he was lobbying to go back in. We decided to not have him go back in, and then he actually felt fine after the game. Then he woke up on Friday morning and didn't feel so good and (the back) stiffened up on him, and that's when we did the MRI. And that's what we found."
The Cowboys went 4-12 last season, including 1-11 with three backup quarterbacks, as Romo missed 12 games.