Lane Kiffin, the head football coach at the University of Mississippi, said Saturday that he had tested positive for the coronavirus and would miss Monday night’s game against the University of Louisville, the season opener for both.

Every player and coach in the Mississippi football program is fully vaccinated — a point of pride for Mr. Kiffin, 46, in recent weeks — and the coach said in a statement on Saturday that he was “experiencing only mild symptoms.” He said no players were expected to miss Monday’s game, which will be played at a neutral site in Atlanta, and that no one else in the football program had tested positive.