Those exemptions end when the rosters have to be trimmed to the final 53 by next Sunday at 4 p.m. Eastern Time.
Heupel appeared in only one preseason game this summer, completing 4 of 8 passes in the 17-10 loss to St. Louis in the Hall of Fame Game.
The rookie sustained a sprained left wrist in that contest, an injury that killed whatever chance he had at making the roster.
While no one ever will question Heupel's knowledge of the game or his work ethic, his arm strength simply wasn't up to NFL standards. That was the reason he lasted until the sixth round of the NFL draft despite leading Oklahoma to the national championship last season.