Nathan Creer was arrested after an argument at Memorial Stadium during Saturday's game against Michigan State, university police Chief Jeff Christensen said.
The argument involved at least five people, Christensen said. He did not know what it was about but said alcohol appeared to be a factor.
"(Creer) resisted and obstructed the officer's efforts to remove him from the incident," Christensen said. "He became somewhat aggressive with the officer."
No one was injured.
Creer, 51, pleaded not guilty Monday to resisting an officer, a misdemeanor, and is scheduled for a pre-trial hearing Dec. 17, according to Christensen and Champaign County court records. Creer and the public defender assigned to his case did not immediately return phone calls seeking comment.
Illinois football coach Tim Beckman called Creer's arrest unfortunate but said it should not reflect on Scheelhaase.
"(Scheelhaase is) a great young man and I know he'll be able to work through the situation," Beckman said. "Nathan can (only) control what Nathan can control."
Scheelhaase said preparing for Saturday's game at Penn State has helped him to not get too rattled by what his father is facing, according to The (Champaign) News-Gazette.
"I've kept it as a family matter," Scheelhaase said after practice Tuesday. "When you're a senior, you've kind of been through the whole gambit. You know there's going to be different distractions throughout your career, and the best thing I have is I have a bunch of people in here who are focused on this next game, focused on what we need to do every day."
Creer, who played college football at Iowa in the 1980s, was given a letter banning him from the Illinois campus after his arrest, Christensen said.
The police chief said issuing such a ban is "standard practice" when someone who isn't a student or university employee is suspected of creating trouble on campus. About 170 are issued each year, he said. They can be appealed, he said, adding that Creer has not yet appealed his.
Violating the ban can result in a criminal trespass charge, Christensen said.
Creer was already on probation after an earlier misdemeanor trespassing conviction, Champaign County State's Attorney Julia Rietz said.
Because both charges are misdemeanors, Rietz said she doesn't plan to try to revoke Creer's probation.