Notre Dame and USC are set to add another installment to one of college football's most storied rivalries on Oct. 18 when the Trojans travel to South Bend. But the future of this iconic series is in question.

With the rumors that Notre Dame and USC could be ending their rivalry, how do the Irish replace the Trojans on their schedule?

The long-term future of the annual college football matchups between Notre Dame and USC is murky. Sports Illustrated's Pat Forde reported Monday that USC has "expressed reluctance to enter into a long-term deal" with the Fighting Irish due to uncertainty surrounding the College Football Playoff format.