The student conduct office meets with the accused student and recommends sanctions, which can be appealed to a disciplinary panel. That decision can be appealed as well.
Palk said a student can be found to have violated the Sexual Misconduct, Discrimination and Harassment Policy, even if criminal charges are never filed.
Shannon, a Dallas native, was Oklahoma's leading tackler last season and has appeared in 25 career games over the past two seasons, with 15 starts. He didn't practice with the team Thursday, nor did he participate in Saturday's spring game.
After the game, OU coach Bob Stoops said Shannon was dealing with "personal issues."
The district attorney said he was not personally involved in the decision not to file charges against Shannon and only became aware of the decision this week.