MANKATO (AP) - Former Minnesota Gophers quarterback Philip Nelson has pleaded guilty to a misdemeanor charge stemming from a fight that left a former Mankato football player with a serious brain injury.

Nelson pleaded guilty Wednesday to fifth-degree assault. The 21-year-old collegiate athlete had been charged with two felony assault charges that carried a maximum 20 years in prison. The misdemeanor charge carries a possible 90 days in jail.

Nelson told the judge he didn't know Isaac Kolstad, a former Minnesota State linebacker, but acknowledged they got in a fight last May in Mankato.

A medical expert previously said Nelson's kick to Kolstad's head probably didn't cause his severe injuries and that it was likely the result of a punch by another defendant and by hitting his head on the pavement.

Sentencing is scheduled Feb. 25.