Pullman police say Mizell was arrested Sunday on misdemeanor charges of assault and trespassing. He was taken to jail but released on his own recognizance.
Police say Mizell tried to enter a party at the Delta Tau Delta fraternity house on Saturday night. When he was denied entry, police allege Mizell punched one of the members and then fled.
A native of Tallahassee, Fla., Mizell started nine games at linebacker last season. A team spokesman says coaches are aware of the arrest and conducting their own investigation.