North Carolina coach Larry Fedora has done this sort of thing before, back in 2014, when he used one quarterback at the start of games and another on his team’s third series. Back then it was Marquise Williams, the starter, and Mitch Trubisky, the future second-overall selection in the NFL draft. And back then, it didn’t work all that well.
Eventually, after four games, UNC abandoned the rotation, went with Williams and used Trubisky only sparingly. At the time, nobody seemed to embrace that rotation. Neither Williams nor Trubisky praised the idea, and both said it hindered their ability to discover their rhythm.