That begs the question -- how will both offenses be impacted?
Louisville and Miami meet in the season opener, a rematch of the Russell Athletic Bowl, and Hurricanes tailback Duke Johnson will be among the many new faces who didn't play in the December game.
We already knew both units would look far different than the groups we saw the last time they played, a 36-9 Louisville romp in the Russell Athletic Bowl in December. Louisville lost star quarterback Teddy Bridgewater, who torched the Canes for 447 yards passing. Miami gained a healthy Duke Johnson, who missed the bowl game with an ankle injury.
Johnson brings a new dynamic to the matchup at running back. But so does new Louisville coach Bobby Petrino, who runs a completely different offense than the one Miami could not stop last season. Parker was set to be the focal point of that offense, a 6-foot-3, 211-pound freak of an athlete with the capability of having a 1,500-yard season.
But with a new starting quarterback in Will Gardner, there is little doubt Parker would have been a security blanket of sorts and the immediate go-to player among the receivers. The other players are solid, but Parker is the one with first-round NFL draft potential thanks to his size and speed (he runs a 4.34 in the 40-yard dash).
Miami gets the benefit of having a stronger Johnson back on the field. His impact on this team is undeniable. With him, Miami was ranked No. 7 in the nation last year. Without him, the Canes dropped four of their final six games. In the Russell Athletic Bowl, Johnson stood on the sideline and watched Miami running backs muster 73 total yards on the ground.
It is obviously huge that he is back. But with a true freshman under center, one has to assume the Cards' defense will be geared toward stopping Johnson and making Kaaya beat them. Kaaya has the skill players around him to help, but the pressure will rest squarely on him to make the right reads and the right decisions in the face of all the pressure.
How will he handle that? Maybe even bigger -- how will he handle the spotlight, making his first start on the road in front of a nationally televised audience? Miami coaches have praised Kaaya for his unflappable demeanor, and say they have run him through pressure situations in practice.
But no practice simulation can prepare a freshman for the bright lights that await, especially as the Miami quarterback. Though Louisville lost some of its best players on defense and will be employing a new scheme, the Cards do return Lorenzo Mauldin (9.5 sacks), linebacker James Burgess (72 tackles) and top cover corner Charles Gaines to make life difficult for Kaaya.
It is plain to see the differences are everywhere. Kaaya and Parker just add to that theme, making this matchup perhaps the most difficult to predict heading into Week 1.