Josh Rosen is going back to school, although he's getting schooled right now.

The rookie from UCLA, who left after his junior season and was majoring in Economics, was asked about his biggest challenge on and off the field. Going back for his degree came up.

"I think off-the-field, that might come when I try to fill my time in the offseason," Rosen said with a smile. "I'm trying to go back to school, actually, so trying to pass those classes might be a substantial challenge."

That's down the road, of course. If anyone worried about Rosen's varied interests impacting him playing football – and it was a criticism of Rosen from some as he came out in the draft – they shouldn't be. He acknowledged he is "all ball" as he tries to learn the NFL game. His biggest challenge on the field, and there are many as he preps for his first NFL outing in Saturday's preseason opener, is just as daunting as any potential Economics class in the future.

"For the most part on the field, (the challenge) has been the complexities of the defenses and sort of all the positions on defense are blending into one," Rosen said. "DBs are getting bigger, linemen are getting smaller but DBs aren't losing any quickness and D-linemen aren't losing any of their strength. Buc (Deone Bucannon) is a safety who turned into a linebacker but still moves like a safety. (Defensive end) Chandler Jones can drop into coverage and play linebacker. That's the biggest thing. Defenses can do anything they want because they aren't really bound by the same rules that they used to be by body types."