The Cardinals coach opened Monday's news conference by announcing that Bonnafon's father, Wallace, had died. The school said that Wallace Bonnafon died from heart failure but did not provide further details. Petrino, who said he spoke with Reggie Bonnafon before addressing the media, did not say what the quarterback's availability will be Saturday when Louisville (2-1) plays at Florida International (1-2).
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.''
On the field, Petrino said sophomore starter Will Gardner will have to play better after his shaky performance in a loss at Virginia that opened the door for Bonnafon to possibly get more playing time.
Gardner returned from a first-half benching following his second interception to direct two fourth-quarter scoring drives that briefly put the Cardinals ahead. But he couldn't mount a last-ditch rally and Louisville suffered its first Atlantic Coast Conference loss (23-21) to fall out of the Top 25.
Bonnafon was 6-of-9 for 39 yards when he was leading the team but the offense stalled as Louisville fell behind 20-7.
With the bulk of their ACC schedule looming after the Cardinals face the Golden Panthers, Petrino stressed the urgency for Gardner to grow after he completed just 14 of 34 passes for 164 yards with two sacks and had several passes batted down.
The coach blamed some of those deflections on the offensive line's failure to sustain blocks, allowing defenders such as 6-foot-5 Cavaliers linebacker Max Valles to easily swat passes.
''It's all 11 guys,'' Petrino said, adding that Gardner sometimes tipped off his throws.
''Will sometimes looks to where he's going to throw the ball too soon and gives the defensive end the opportunity to see where his eyes are,'' Petrino said.
''We've been working hard with Will all fall to set and stand tall in the pocket. He has a habit sometimes of staying crouched and not getting back leg under his back hip, which raises you up and allows you to deliver over the top of things. Some of it was, although he's 6-5, he wasn't throwing the ball from the stature of 6-5.''
Louisville's offensive problems weren't limited to quarterback play.
The Cardinals allowed three sacks and mustered just 282 yards including just 79 rushing against the stingy Cavaliers. Their receivers failed again to get that long completion that Petrino seeks.
With senior wideout DeVante Parker out at least a couple more weeks with an injured left foot, someone has to step up as the deep threat. Petrino's priority is making sure his QB gets the ball there on time, no matter who's in the pocket.
Petrino is used to young QBs enduring growing pains, having guided Brandon Doughty through them just last fall at Western Kentucky. Doughty threw eight interceptions in two early losses and didn't start the next contest; he recovered to reclaim the starting job, lead the Hilltoppers on a season-ending four-game winning streak and throw for a school-record 2,857 yards.
That example provides hope for Gardner, whom Petrino praised for bouncing back from his benching to rally Louisville for a short while. The challenge for his young QB is locking in mentally and mechanically for the whole game - especially against an FIU squad intent on avenging last year's 72-0 thumping in Louisville.
''The biggest thing they have to understand is that they're not the only quarterback that's going to go through this,'' Petrino said of dealing with a player's psyche, citing former NFL Jacksonville Jaguars star Mark Brunell as an example. ''It's just the nature of the position. You have to be able to focus and keep your eyes downfield.
''It's just sitting down, visiting with them and then them going out and working extremely hard to correct those things.''