Pettis suffered a lower-leg fracture on a failed two-point conversion in the Broncos' win over Nevada.
Peterson said there's a chance that Pettis could return for BSU's bowl game, which is expected to be a BcS game after the first of the year.
The junior's 62 receptions and 850 yards are both second on the team, while his 14 touchdown catches are tops on team.
