ENGLEWOOD, Colo. -- It is a destination of sorts, even a starting point, a place some are told they have to go, have to get in and stay in. It is the foundation, what Denver Broncos cornerback Chris Harris Jr. calls “everything."

It is routinely still called a book, except it isn’t for most. But how quickly, how efficiently, how thoroughly an NFL player can dig in and master his team’s playbook can determine how their careers begin. And as training camps around the league pound their way to the day when rosters are cut by some 41 percent, the way a player commits his playbook to memory can go a long way toward getting a first chance, let alone a second.

“Biggest mistake a young guy makes? Not putting the time in," said Broncos coach Vance Joseph. “And if they fall behind early, most never get that back, most never catch up. If you get a rookie in and he struggles all year to learn and to study, even if he makes that next year, he’s a year behind, he never catches up. And a lot of the time he doesn’t even get that second year."

While it might not doom them, sometimes the same learning curve applies to free-agent signees, notably quarterbacks.

Signal-caller Case Keenum, who signed with the Broncos in the offseason after stops with the Texans, Rams and Vikings, has created what he calls “my process.” For Keenum, it involves a combination of the old school and the new school.

“Just saying it [the playcalls] over and over again, that really gives me the foundation, to actually go through the words, every play,” Keenum said. “My wife still quizzes me, she still helps me get it done ... it’s one thing for me to read it and learn it, but to hear it and visualize it, that just helps me. I say it and picture it, like from above.”

Gone are the days, at least for the most part, of three-ring binders, jammed with sheets several inches thick of plays and diagrams, of $100-a-page fines for the inevitable one or two binders that got lost each summer. It’s all on tablet devices now -- practice video, game video, play diagrams, notes, bullet points. It’s all there.

“And the bottom line is everybody learns differently,” Joseph said. “You’re not teaching one way to one person; your goal is to get everybody the information so they can be their best and you can see their best. And you can’t do it until you know it.”

Keenum, like many of the team’s coaches, including Joseph, also still uses a paper playbook in addition to the electronic version.

“... I guess I’m just not millennial enough to go all the way in,” Keenum said.

“I can draw on the paper, put my notes; you’re not worried about keeping it charged, and I make notes to myself of things I want to remember about a lot of what I’m looking at.”

But the search for the learning plan that works is always on, it seems. Joseph said that over the past four years as an assistant, and now as a head coach, he has found the use of the tablets has enabled coaches to give players a head start. Coaches can electronically put in bullet points -- things to remember -- in each play diagram and deliver all of the information electronically in one motion.

The Broncos can still, and do, have players take their own notes in meetings, but with many of the most-common questions already answered in the playbooks, the players can keep their eyes on the video screens more of the time in meetings rather than in their notebooks as they try to keep up with what’s being said.

"When they walk into a meeting, they don’t have to stress about whether or not they’re going to get the right notes,” Joseph said. “ ... We give them the diagrams, but inside each formation, each diagram, we give them notes, so they don’t spend time with their heads down while you’re teaching. In the past, you give a guy a notebook and say ‘take notes,’ and we discovered he spends half his time, two-thirds of his time with his head down in the meeting instead of looking at the screen, instead of paying attention to the teaching.”

Some players, whether they admit it or not to their coaches, face steep challenges. Former Broncos lineman and current Fox NFL analyst Mark Schlereth said he usually didn’t openly discuss his dyslexia with his coaches in the NFL. That was because by the time he started his 12-year career, he had developed his own system to commit the playbook to memory.

His hurdle, and no small one at that, was he couldn’t do that like most people he worked alongside.

“I had learned, by the time I got to college, with my learning disability, that buying a textbook that wasn’t math, wasn’t statistics, that wasn’t predominantly diagrams, was going to be a colossal waste of time for me,” Schlereth said. “To this day, reading out loud from a printed page is a challenge. I had to spend more time, a lot more time, with film, with the diagrams than other people maybe, and I had to be a copious note-taker; I had to put the information in my own voice, and then I could digest it.”

In addition to all of the extra work with the game video in training camp or in the regular season, Schlereth said he had to spend hours the day before every game making notes on what he would do on each play or in each scenario he could face.

"Just saying it [the playcalls] over and over again, that really gives me the foundation, to actually go through the words, every play. My wife still quizzes me, she still helps me get it done." Case Keenum

Those notes included details as fine as the individual steps he would take and where he would put his hands.

“My notes on one play, with just one look by a defense, might say ‘jab step, not too big, get your head in a certain place, where I put my hands,'” the three-time Super Bowl winner said. “For every scenario, for every play, page after page. I just had to see it that way, and if it came up in a game or practice, I could remember what to do. It meant I wasn't much fun to sit next to on the plane sometimes because I had to be in my notes.”

In the end, however, it all might start and end with the player holding the iPad or the pen and the paper.

“Ain’t no shortcuts, ever,” said Broncos wide receiver Demaryius Thomas. “Just over and over again, look at it, read it. Again and again. Guys who have trouble, maybe some guys have a harder time, but usually it’s they didn’t spend the time it took. If it takes you longer, then spend more time. Your only chance is to spend as much time as it takes.”