The school said Wallace Bonnafon died of heart failure but had no other details.
Petrino said Monday that the QB told him about his father. The coach asked that "everybody's prayers and thoughts go to Reggie and his family as he works through this. ... It's certainly going to be a trying time."
Petrino did not say what Bonnafon's status is for Louisville's game on Saturday at Florida International.
Bonnafon has played in the Cardinals' last two games. The Louisville native replaced sophomore starter Will Gardner in the second quarter of Saturday's 23-21 loss at Virginia and completed 6 of 9 passes for 39 yards before Gardner returned in the fourth.