Kiffin said in a statement that he had developed a breakthrough case of COVID-19.
"I am grateful to be vaccinated and experiencing only mild symptoms. So much so, I debated over being tested, but I'm relieved that I did," Kiffin said. "I'm proud of our program's commitment to vaccination, and as a result, there are currently no other cases to report or team members expected to miss the game."
Ole Miss said it has not yet decided who will handle the head-coaching duties Monday for the Chick-fil-A Kickoff Game in Atlanta.
Kiffin said earlier this month that there was a 100% vaccination rate among Ole Miss players, coaches and staff members. He touted that fact in an interview with ESPN's College GameDay on Saturday, noting that a number of players -- including starting quarterback Matt Corral -- could have been forced out against Louisville as close contacts of Kiffin if they were not vaccinated.
He added that it was tough to tell players about his positive test after experiencing symptoms starting Thursday.
The 46-year-old coach is starting his second season with the Rebels after going 5-5 in 2020.