CLEVELAND -- Browns Hall of Fame running back Jim Brown has cancelled a speaking engagement with NFL rookies because of an illness.

Brown had been scheduled to conduct a history lesson for AFC rookies on Wednesday at the Pro Football Hall of Fame in Canton. However, the 77-year-old Brown said in a statement that he is extremely tired from extensive traveling and needs rest. Brown said he was sorry he will miss the event, part of the NFL's Rookie Symposium. Fellow Hall of Famer Mike Haynes will replace Brown.

The NFC's rookies will visit the hall on Saturday and will get a lesson from Bears great Richard Dent.

Brown recently was hired as a special adviser by the Browns, reconnecting with the team after several years.

One of the reasons the league is holding the symposium in northeast Ohio is its proximity to football's birthplace. It's a chance for the players to connect with the game's immortals who all began as wide-eyed rookies.

During the annual symposim, first-year players are getting a crash course into everything that goes into being a professional athlete -- the good, and the bad. The NFL wants its newest members to be prepared not only for what awaits them this season, but for the years ahead, especially those days when they're no longer making big paychecks or big plays.

Through various educational seminars, candid, sometimes heartbreaking speeches and panel discussions, players are learning the X's and O's of life.

The AFC's rookie class arrived in Aurora, Ohio, on Sunday to begin the four-day session, which the league has constructed as a teaching and bonding experience. The NFC rookies arrive Wednesday and stay through Sunday.

"It's a great opportunity for us to be out here learning from players who've been here, been in our shoes and who are where we want to be," said San Diego Chargers linebacker Manti Te'o, the former Notre Dame star who this year was the target of a hoax involving a fake girlfriend. "As we get into the next phase of our lives, it's a new phase, something we're not used to, so to keep our circle small and remember the people who have always been there for you."

On Monday, players attended a seminar titled: "Are You Bigger Than The Game?" that featured Cincinnati cornerback Adam "Pacman" Jones and former Ohio State star running back Maurice Clarett as speakers.

Jones recently pleaded not guilty to a misdemeanor assault charge and has had other off-the-field issues that led to league suspensions. He talked frankly about his many errors and warned players about them.

"He's always been a guy who has preached don't do the same mistakes he's done," said New York Jets rookie quarterback Geno Smith, who knows Jones because both played at West Virginia. "He's made a lot of mistakes in his career, but he's a guy who is still standing strong and still working hard. He's using his past trials and tribulations to try and help us."

Because Jones is still an active player and Clarett's story is well documented, their messages resonated with the young players.

Clarett urged the players to stay straight. His promising pro career was derailed by legal troubles not long after he helped lead the Buckeyes to their first national title in 34 years. Clarett wound up serving 3½ years in prison.

Information from The Associated Press was used in this report.