If anything were to happen with Morris, the Canes would likely turn to Ryan Williams (Jr). The former Memphis transfer played sparingly in 2012, including the final few minutes in the loss to North Carolina. He doesn't have anywhere near the skill set or experience as Morris, so he'd have to grow up in a hurry if he saw any meaningful snaps.
Gray Crow (R-Fr) seemed to pull ahead of Preston Dewey (R-Fr) for the third spot back in the spring. Both players were fairly lightly recruited coming out of high school and neither has made huge strides in their development here yet. They'll likely have to hold off the challenge from true freshman Kevin Olsen for the third spot.
Olsen is the first elite quarterback prospect the Hurricanes have signed in several years. He's the player Al Golden and Jedd Fisch wanted from the day they got here. They got him, he's on campus now, and all signs point to him being the future at the quarterback position for the Hurricanes.
Look for the coaches to give the four backups lots of opportunities during preseason camp. They know what Morris brings to the table, and they'll likely do everything they can to keep him fresh and healthy heading into week one preparations. It'll be interesting to see if Williams can hold off Crow (or Dewey) for the number two spot, and how quickly Olsen can rise up the depth chart.