ENGLEWOOD, Colo. — For as much hype as there has been surrounding the Broncos' rookie class, it's important to clarify one important note.

This isn't easy.

Not the physical aspect, not the maturity aspect and not the mental aspect. None of it.

The transition from collegiate star to NFL player is difficult, and while players like Bradley Chubb, Courtland Sutton and Royce Freeman have been impressive, that doesn't mean they have all the answers.

Head Coach Vance Joseph stressed that point Monday and noted that the rookies and other young players must commit to studying their playbooks — even as the demands of training camp increase.

"It's tough on rookies," Joseph said. "We had a rough day today with some of our young guys. The more you practice and the more you install, they have to study more. We had some guys today that struggled with their assignments. That's all rookies, even the really mature ones.

"They've got to understand it's first, second, third down, it's punt team, it's punt return, it's kickoff — it's a lot that goes on with being a football player. The more we put in, the more we practice, the more they have to study and that's a deal with all rookies."

After initially installing the entire offense during the offseason program, Joseph said Monday the Broncos have reinstalled 35 to 40 percent of their offense during the first few days of training camp.

But because the Broncos already went over the entirety of their offense in OTAs, the information isn't new.

"We've put everything in in the spring on both sides of the ball," Joseph said. "Here's why: In my opinion, the spring is for guys to stretch their minds. We give it all to them, even though it doesn't look pretty sometimes, but at least they've heard it."

That, Joseph hopes, will help the Broncos later in the season if they need to add plays to the game plan against a given opponent.

"That way in the fall, when you're in Week 8 or 9, you're not reinventing the wheel for players," Joseph said. "You may not call those plays until Week 8, but at least they've heard them. If they've heard them, they can get them during the week. If they haven't heard it, it creates anxiety for players, it makes them nervous and they don't get it right. Our install is heavy, just because we want a big library so we can survive the season without reinventing the wheel in Week 8, 9 or 10."

For now, Joseph just needs his young players to focus on and learn the current iteration of the playbook.

They'll get there as training camp progresses — it just may take a little extra work.