Sills, a seventh-grader and the starter at Red Lion Christian Academy in Bear, Del., can't officially sign a letter of intent to his "dream" school until 2015, when he graduates from high school.
He is among the youngest to receive a scholarship offer from a major-college football program.
"It just happened out of nowhere," Sills told the newspaper Friday.
Sills says he made his decision after Steve Clarkson, a private quarterbacks coach, convinced new USC Coach Lane Kiffin to watch a video of Sills on his (Clarkson's) Web site.
Clarkson has tutored former college quarterbacks Matt Leinart (USC) and Jimmy Clausen (Notre Dame), and Matt Barkley, USC's starter last season when he was the Pac-10 school's first-ever freshman starter at the position.
Leinhart led USC to back-back national titles in 2003 and '04, and now plays for the Arizona Cardinals.