"I know it's a bad look," Luck told reporters during a conference call Wednesday. "My girlfriend tells me every day. My mom tells me."
"I realize it's a bad look. But I'm not going for any specific look."
Luck and the Colts visit the Broncos in an AFC divisional playoff game on Sunday.
The third-year quarterback said it has nothing to do with superstition. Instead, Luck, who led the NFL with 40 touchdown passes during the regular season, said that he just doesn't like shaving during the season.
"Razor burn," Luck said. "If you grow it this long, you might as well keep it."