Notre Dame has had its share of quarterback issues this season, but it won't be the only team Saturday dealing with a quarterback problem.
USC's John David Booty broke a finger on his throwing hand two weeks ago during the Trojans' 24-23 loss to Stanford.
Last week, Trojans backup Mark Sanchez got his first career start and was 19-for-31 for 130 yards, one touchdown and two interceptions in USC's 20-13 win over Arizona.
Booty and Sanchez are very similar quarterbacks, although they have slight differences - mostly regarding mobility.
Sanchez impressed Trojans coach Pete Carroll with his ability to make plays happen outside of the pocket.
"When you're scrambling and you take off and run, it's like everything that you ever known in any sport comes into play," Carroll said in a press conference Tuesday. "It all comes to the front immediately, and you have to react and use your vision and your peripheral vision and sense and awareness and your athleticism and your gut and all that."
While Sanchez's ability to makes big plays out of seemingly nothing is a definite positive, Carroll said, he needs to harness that ability so that he does not give up on the designed play too quickly.
Sanchez "has more of a variety of things that he'll create with the football in his hands," Carroll said. "You know, we have to corral that. You have to harness that so that it doesn't work against him and take him out of the normal rhythm of plays that could be executed."
Carroll said Booty represents more of a traditional pocket passer.
"John was a football player that was a quarterback that was a shotgun-in-the-pocket guy," Carroll said. "He's more of that kind of a football player, and he's really, really good at it."
But regardless of who starts for USC, Notre Dame coach Charlie Weis said the Trojans' system warrants the most attention.
"I think that if you [focus on the quarterback] you set yourself up for failure because it's not like they're bringing in a speed option quarterback versus a drop back quarterback," he said. "They have their system in place, so therefore, you can get ready for their system instead of getting ready for their quarterback."
Irish defensive coordinator Corwin Brown agreed.
"You prepare for the system that they run. It's not like one runs an option and the other is a drop back passer," Brown said. "It's the USC system that you have to prepare for, and that's enough. So you just prepare for what they do, no matter who is back there."
Weis did say the most important difference between the two quarterbacks that could be a factor on Saturday is Booty's experience. Booty started every game last season after being former Heisman Trophy winner Matt Leinart's primary backup. Sanchez has only started one game and threw just seven pass attempts last season in late game situations behind Booty.
"I think that Booty's experience expands the playbook. I think that any time you have a more experienced guy you can do more things," Weis said. "Obviously playing Sanchez is not going to stop them from running the offense. They're not going to change the offense; I just don't think they'll do as much."
Going into the Notre Dame game, Carroll is confident in both his quarterbacks. Even if Sanchez plays, Carroll said, he will not have to be spectacular to give the Trojans a chance at winning.
"Mark needs to play a good, solid football game if he's in there, and keep us in the game and not make any critical errors that could give the other team a chance," Carroll said. "That's all we need him to do. We don't need him to carry us at all."
