Source: Johnny Manziel apologizes

Texas A&M quarterback Johnny Manziel has apologized to the Aggies' coaching staff and is being advised to be honest about what led to his much-discussed departure this past weekend from the Manning Passing Academy, a source told ESPN.

The Heisman Trophy winner did not finish his scheduled stay as a college coach/counselor at the camp at Nicholls State University in Thibodaux, La., because he missed assigned meetings and practice sessions, citing dehydration and illness. He apologized privately to camp officials for being unable to fulfill his commitment.

According to some Internet reports, Manziel was sent home by Archie Manning because of "partying," although ESPN's Chris Mortensen reported that camp officials were adamant those reports were inaccurate.

Manziel, who is scheduled to speak at SEC media days Wednesday, was "very upset" as he headed home from the academy and has privately conceded that he needs to continue to mature, the source said. He is preparing for an anticipated difficult line of questioning at media days. The turnout of media is expected to number around 1,200.

Manziel prepared diligently before his speech and media availability at the Heisman Trophy ceremony, and he's planned the same heading into the SEC appearance, according to sources.

Among those who have advised him are university coaching staff and media and public relations specialists. Manziel has been told to anticipate and prepare for a circus-like atmosphere and off-the-wall questions that have become commonplace at the event.

The 20-year-old sophomore has made numerous headlines this offseason through his social media accounts, destinations he has traveled to and celebrities he has encountered. On Monday, he pleaded guilty to a charge that he failed to identify himself to police and saw the remaining charges against him dismissed during a hearing stemming from his arrest in June 2012.