NFL Network's Ian Rapoport reports the Cowboys are leaving "the door cracked slightly" for Dak Prescott to supplant Tony Romo (back, out indefinitely) as the starter.
With Romo out until at least the middle of October, Prescott will get the opportunity to make several starts early in the year. If he shows like he did in the preseason, the Cowboys -- who have already invoked the names of Drew Bledsoe and Tom Brady -- would have a tough time sending the rookie to the bench. Prescott is unlikely to play at that level, however, and Romo will almost certainly be the starter whenever he is healthy.
Source: Ian Rapoport on Twitter