With Kellen Moore (ankle) out of action potentially until December, Prescott is currently listed as Tony Romo's backup on the QB depth chart.
There's almost zero chance the Cowboys will head into the season with a raw rookie backing up the fragile Romo, so expect them to explore the trade market for a signal-caller with more experience. Until that happens though, Prescott will get valuable extra reps in camp which can only help in his development. He's still a long shot to see meaningful snaps as a rookie, however.