Matt LaFleur, left, is the quarterbacks coach for the Washington Redskins. One of his jobs is to quiz Robert Griffin III, right, on the playbook that the rookie needs to learn. (John McDonnell/THE WASHINGTON POST)

The Redskins’ preseason training camp is underway. Washington football fans are psyched about Robert Griffin III, the team’s rookie quarterback. They can hardly wait for Griffin to start sprinting downfield for big gains and throwing touchdown passes.

But I hope all the kids who are buying RGIII shirts and styling their hair like the Redskins quarterback notice what Griffin has to do during training camp to get ready for the 2012 season.

Study: The Redskins’ playbook is five inches thick and filled with hundreds of pages of plays and formations. As quarterback, Griffin has to know what to do on every offensive play and where every one of his teammates will be.

A recent Post article reported that Griffin and Kirk Cousins, the Redskins’ other rookie quarterback, study the playbook together every night. They take quizzes on the playbook prepared by Kyle Shanahan, the team’s offensive coordinator, and Matt LaFleur, the quarterbacks coach.

Reports are that Griffin is a good student. After all, he graduated from Baylor University in three years. (College usually takes four years.)

Listen: Griffin was a great college quarterback. In his final season at Baylor, he threw for 37 touchdowns and ran for 10 more. Griffin won the Heisman Trophy as the outstanding college football player during the 2011 season.

Still, he has to learn how to play the faster and more complicated pro game. The Redskins coaches will give Griffin lots of pointers about how he can improve his footwork, throwing delivery and ball-handling.

Griffin has to listen and then try to do what the coaches tell him. If he acts like a know-it-all who’s already a superstar, he won’t get much better. And both the Redskins and Griffin will be in trouble.

Work well with others: Rookies in the National Football League (NFL) are like the new kids at school: They have to try to make friends and fit in with the team.

So I don’t think you’ll see Griffin acting like a big shot or bragging about what a great player he was at Baylor. Pro football players are not impressed with college stuff. Most pros were good in college. They want to see whether Griffin can make big plays when it counts: on Sundays during the NFL season.

Griffin has to earn the respect of the other Redskins with his hard work and hustle every day at practice. He has to show everyone he will be a good teammate.

Being a football player — even one as talented as Robert Griffin III — is not all running and throwing. Pro athletes also have to study, listen and work well with others.

Not a bad way for anyone, even kids, to get started in something new.

Fred Bowen writes the sports opinion column for KidsPost. He is the author of 18 sports books for kids, including two football books. His latest book, “Go for the Goal!,” has just been published.