The clock is ticking.
With each passing day, each passing week, the USC football season gets closer and closer.
As the year approaches, the depth chart is sure to shift, positions will be shuffled and incoming freshmen will have a chance to crack the Trojan rotation.
In preparation for the year, USCFootball.com will break down each of the positions on the team.
In the first installment, we'll look at the quarterback position.
In 2007, the USC football team had one of the most valuable commodities any football team can have — a senior quarterback.
John David Booty completed over 63 percent of his passes for 2, 361 yards, 23 touchdowns and 10 interceptions. Booty, USC's sixth all-time leader in passing yards, saved his best for big games — leading the Trojans to a perfect 9-0 record against AP ranked opponents.
Booty started 10 of USC's 13 games, missing starts against Arizona, Notre Dame and Oregon. After breaking the tip of his middle finger on his right hand, Mark Sanchez took over.
The Minnesota Vikings selected Booty in the fifth round of the NFL Draft.
An open competition during the spring between Sanchez, Mitch Mustain and Aaron Corp ended before the Trojan Huddle with Pete Carroll naming Sanchez the starter.
Sanchez has embraced the role in summer workouts, oozing leadership at every opportunity.
And, it's nothing new.
"I wouldn't say there's a difference in him. Mark's always been a leader, especially last year," sophomore receiver Damian Williams said. "He'd take the underclassmen under his wing and show us what we need to know."
In three starts and five other appearances last season, Sanchez completed 60 percent of his throws 695 yards, seven touchdowns and five interceptions.
In summer workouts, the Sanchez-led offense has struggled some against the Trojan defense. However, he's shown good accuracy on the deep ball and good arm strength on sideline routes.
Likely backing Sanchez up this season, Mustain enters his first year of eligibility since transferring from Arkansas.
Though Carroll has named a starter, Mustain's still battling.
"I'm not done competing for anything..." Mustain said. "I feel pretty comfortable with the system, but I'd like to always get a lot better with it. I'm just trying to cram as much in and see what happens."
Mustain's looked solid in summer drills so far, and he should be one of the top backups in the country.
Corp, one of the stars of the Trojan Huddle, hasn't backed down either.
Corp's shown good poise in seven-on-seven drills and has a combination of size and athleticism unmatched at his position on the Trojan roster.
Between Sanchez, Mustain and Corp, the Trojans have three strong candidates to lead the team.
Sanchez's leadership helps him stand out, but the question remains — is leadership enough.
Offensive guard Zack Heberer thinks so.
"Mark takes a lot of pride in being a leader and in taking control out here," Heberer said. "He's looking out for all of us.
"I don't want to let him down; none of us do."
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