Cale Gundy, a fixture on the Oklahoma sideline and the longest-tenured football coach in the Big 12, resigned Sunday night, saying that he read aloud "a word that I should never -- under any circumstance -- have uttered" off the screen of a player's iPad during a film session last week.

Gundy, 50, the younger brother of Oklahoma State head coach Mike Gundy, played quarterback for the Sooners from 1990 to 1993, setting nearly every school record by the time he graduated.

First-year Sooners head coach Brent Venables, who served as an assistant alongside Gundy from 1999 to 2011 in Norman, issued a corresponding statement Sunday night.

"I recognize this is a critical moment for Oklahoma football," Gundy wrote