Josh Rosen is a rookie, but he's more familiar with Sunday's venue of the StubHub Center than most of his teammates.

Rosen was the quarterback for St. John Bosco in high school, and in his junior season, he led his team to a 16-0 record -- including a memorable 20-14 win over powerful De La Salle at StubHub, giving Bosco not only a California state title but also a mythical high school national championship nod.

"Yeah, it was fun," Rosen said. "I just remember that I had a rushing touchdown in that game that was called back on the first drive, which was unfortunate. I think we snapped a pretty big winning streak of De La Salle's. It was a very fun year, going 16-0. I have played a 16-game season before. It was a lot of fun. High school football is a lot of fun."

De La Salle had won 67 straight before the loss.

Rosen acknowledged he may briefly think about that night when he gets to the stadium Sunday.

"There's a spot on the wall that I'll definitely remember when I jumped up over the crowd to hang out with some of my buddies," he said. "Got some photos of holding the state championship (trophy) with all my friends in the staff. I might try to spot that part in the wall, but for the most part, not too much."

Is there any advantage to Rosen having played in the building before, in terms of Sunday's game with the Chargers?

"No," Rosen said. "Not really."