But two brothers, Antoine and Brandon Sharp, have made the job much easier for Petrino and his defensive staff.
Antoine, a senior transfer from the University of Florida listed No. 1 at strong safety on the depth chart, and Brandon, a junior penciled in as the starter at free safety, have played well during fall camp, according to Petrino.
"Brandon's been there for two years so he doesn't seem new to me," Petrino said. "He's doing a nice job of tackling and that's one of the major concerns that I have. I know they can [both] cover the pass and break on the ball but they have to tackle."
As U of L's last line of defense, tackling and being physical are major job requirements. Fortunately for Petrino, neither of the Sharp brothers appears shy about delivering a big hit. If you need proof, simply turn on last season's tilt with Miami in the Orange Bowl and fast-forward to the blow Antoine delivered to Hurricane's quarterback Brock Berlin on a corner blitz.
"Antoine's always been very physical," Petrino said. "When he played nickel and corner a year ago he was very physical. So those two guys are doing a nice job."
Brandon Sharp will team with brother
Antoine this season at safety.
"No question about it," Petrino said of the experience Sharp gained a year ago. "That and the fact that he played nickel because he moved in and covered the slot receiver all the time and that's what you have to do at safety. So he has the experience on understanding the different routes that [receivers] run at that position. And that helps him a lot."
And with an entire spring to learn his new position, Antoine Sharp says he's finally become comfortable at safety.
"The transition is going very well," Sharp said after Wednesday's practice. "I feel very comfortable [at safety] and I feel as if I can make plays back there – I have been make plays through two-a-days."
Sharp also thinks it is a tremendous benefit to have his brother Brandon next to him on the field.
"It's a cool experience to have my brother there because we communicate [so well]," he explained. "We don't even have to talk, we can just read each other's body language or look at each other a certain way and we know what we're talking about."
Even with Antoine and Brandon Sharp firmly entrenched with the first team defense, Petrino is still looking for more depth to emerge behind his two starters. In fact, if the season opened today, sophomore Jon Russell would pull double-duty backing both Antoine and Brandon up.
"Jon Russell is the guy right now that's stepped up and would be the backup at both positions if we needed to go today – luckily we don't," Petrino said. "So we're going to continue to bring another guy around."
Though the defense might lack depth at safety with the season rapidly approaching, Antoine Sharp believes the defense can be as good, if not better, than last year's nationally-ranked unit.
"The defense is doing great," Sharp said. "We're just out here working hard, fighting through two-a-days and trying to get better every day."
And while there will be five new starters on the defensive side when the Cardinals take the field against Kentucky for the time this season September 4, Sharp says the ‘new look' Cards won't look so different from last year's squad.
"This is a new group of guys but we basically have the same mentality – the ‘red swarm' mentality," Sharp said. "We run to the ball fast and we're all eager to make a play. We can be better than last year's defense. We have a lot of guys coming back and we're very hungry to do well."