FRISCO, Texas – At the start of the Dallas Cowboys’ news conference to kick off training camp in Oxnard, California, owner and general manager Jerry Jones said the days of relying on the return of a player from injury, suspension or whatever are over, especially given how disastrous the 2015 season was.

Heading into last season, the Cowboys thought all would be well with the return of Tony Romo and Dez Bryant from injury and Greg Hardy and Rolando McClain from suspension, only to have their second-worst season of Jones’ ownership.

“We tried that,” Jones said. “We got a doctor’s degree in it. We went to Harvard Business School over it.”

Now that Romo has suffered, according to a source, a compression fracture of his L1 vertebra and could miss six to 10 weeks, that theory will certainly be tested.

The Cowboys went 1-11 without Romo last year (the quarterback broke his left collarbone twice). In his absence, Brandon Weeden, Matt Cassel and Kellen Moore took turns as the starter. The Cowboys lost their only game without Romo in 2014. They lost their only game without him in 2013, too. Over his career, they are 78-49 when he starts and 10-23 when he has been out.

The Cowboys have relied on Romo for success perhaps more than any other team in the NFL has relied on its quarterback.

While coach Jason Garrett and executive vice president Stephen Jones were not ready to put a timetable on Romo's return this season, going so far as to not yet rule him out for the Sept. 11 season opener against the New York Giants, there does not appear to be any question the Cowboys will be playing at least one game without Romo for the fourth straight season.

"Of course, our success without Tony hasn't been good up to this point, but we fully expect to change that this year," Stephen Jones said. "We fully understand why everybody is going to question that, but we feel good about Dak (Prescott). We think our team feels good about Dak. The chemistry is there with the players and that's what we're going to focus on. But we totally understand there's going to be question marks and people are going to question whether we can get it done."

The Cowboys drafted Prescott with the hope that he would be their quarterback of the future, not even the backup of the present. Now he is their likely starter against the Giants. His work in the preseason has been nothing short of phenomenal: 454 yards on 39-of-50 passing with five touchdowns and no interceptions. He has also run for two scores.

But he's a rookie.

"We want all of our players to be able to practice every day and play in every game. That's not the nature of the NFL," Garrett said. "The philosophy that we have is next man up. We have to have that mentality as individual players. We have to have that mentality as a team. And I think our players understand that, and at times we've done a very good job of that in the past. When guys have gotten hurt, the next guy's gone in there and played well. Other times we haven't. It's a critical part to being a good football team in this league, to be able to handle the adversities over the course of the year. Injuries are adversity. Dak has done a very good job up to this point in the preseason, understanding what we're asking him to do and going out and performing."

Garrett informed his players of Romo's injury after the team's conditioning run. While there is an obvious disappointment in losing Romo, who is 15-4 over his last 19 starts, "everyone must keep going," cornerback Morris Claiborne said.

Pro Bowl center Travis Frederick said low morale won't be an issue.

"Still trying to take it in a little bit, but the name of the game -- and the name of the game for us -- has always been focus on taking things one day at a time, and also having the next man in mentality," Frederick said. "Being able to have Dak step up and be able to take over that role, and just support him in any way that we can."