Bonnafon, who started three games earlier this season in place of injured Will Gardner, regained the job last week when the sophomore sustained a season-ending left knee injury in the win at Boston College. He gets to face Notre Dame on Saturday and Petrino said Monday that coaches want Bonnafon to play to his strengths.
After relieving Gardner late in the first half at BC, Bonnafon completed 4 of 5 passes for 69 yards and two touchdowns. He also rushed for 76 yards and a touchdown on 13 carries, another facet that Petrino called a significant difference maker.
''We are asking him to be smart,'' Petrino said. ''You know, make sure he gets the first down and takes care of himself'' when he runs.
This season has been challenging for the young Louisville native.
Besides throwing for 662 yards and four scores in seven games, Bonnafon has dealt with the sudden death of his father in addition to getting ready to start soon after. Petrino said he's been impressed with Bonnafon's attitude and the amount of work he's put in through everything.
''I think every player on our team respects him,'' Petrino said. ''We're all cheering for him to go out there and play really well.''
Though the Cardinals will be without their top QB, they could possibly have a couple of key defensive players back from injuries against the Fighting Irish.
Senior linebacker Lorenzo Mauldin missed the last game at BC with a hamstring injury, but Petrino said his prospects of playing Saturday were very encouraging. There's also a chance that defensive lineman Pio Vatuvei could return from an elbow injury, and Petrino said having the junior back would help the Cardinals against Notre Dame's rushing attack, the coach said.
Sophomore wide receiver James Quick could also return from a suspension prior to the BC game. Petrino said Quick could come back this weekend if he takes care of the requirements placed upon him by the coaching staff.
Louisville's task in South Bend, Indiana, will be continuing its offensive roll after midseason doldrums.
The Cardinals appeared to have found their groove, having scored 30-plus points the past three games. They will face a Notre Dame defense that has struggled of late, yielding an average of 42.2 points over its last five games.
Louisville's fifth-ranked defense meanwhile will face its own challenges against a high-powered Irish attack that Petrino said ''just keeps going and scoring points.''
Notre Dame averages 35.4 points per game, making red-zone success critical for a Cardinals team that has scored touchdowns on just 69 percent of their trips inside the 20 (31 of 45).
Said Petrino, ''You know you're going to have to move the ball and get it in the end zone.''