A former Minnesota State linebacker is fighting for his life after he was allegedly beaten in an incident police say involved Philip Nelson, a quarterback who recently transferred to Rutgers.

The 6' 2", 215-lb. Nelson, 20, has been charged with first- and third-degree assault, according to the criminal complaint released Monday. He has been jailed since shortly after 2 a.m. Sunday when he was arrested in Mankato, Minn., where the alleged attack took place.

His arrest came after officers found Issac Dallas Kolstad, 24, beaten and lying on a street in Mankato.  Kolstad remained in critical condition this morning at Mayo Clinic Health System, according to wire reports.

Kolstad is suffering from a "severe head injury and severe pulmonary injury," according to the criminal complaint as reported by the Minneapolis Star-Tribune website. A surgeon quoted in the complaint is "not optimistic that he will make a good recovery" if Kolstad does survive.

Kolstad recently graduated and was working as a sales representative. He is married with an infant daughter. The couple is expecting another child.

The alleged attack took place in Mankato's entertainment district. Kolstad was unconscious when police found him.

According to the complaint, surveillance video shows Kolstad initially punched Nelson in the back, causing Nelson to fall to the ground. As Kolstad then walks away, an unknown attacker punches Kolstad, causing Kolstad to fall to the ground. It appears, according to the complaint, that Kolstad was knocked unconscious by the punch.

Nelson then allegedly "delivers at least one kick to the left side of [Kolstad's] head," the complaint reads. Kolstad has a fractured skull on the side where Nelson allegedly kicked him.

Nelson is a native of the area. He left the Minnesota State Gophers in January and transferred to Rutgers. He was currently participating in spring practices for the Scarlet Knights.

Nelson played in 11 games for the Gophers last season, sharing QB duties. As part of the transfer, he was going to sit out the 2014 season and then would have had two seasons of eligibility left to play for Rutgers, which is moving to the Big Ten next season.

Police are still looking for the second suspect in the assault.

Nelson's family could not be reached for comment, according to the Star Tribune in Minneapolis. But the newspaper said the alleged assault followed a busy night in Mankato when many were out celebrating graduations.