Former Gophers starting quarterback Philip Nelson is being held for alleged third-degree assault Sunday after an altercation overnight at a downtown Mankato intersection left a man critically injured, according to Mankato city officials.

Mankato police found Isaac Kolstad, 24, near the intersection of Cherry and South Front Sts. around 2 a.m. He was taken to the Mayo Clinic Health System hospital in Mankato.

Nelson, 20, was at the scene and taken to the Blue Earth County jail for probable-cause assault, officials said.  Police said they are looking for another person who was involved in the altercation.

Nelson, a former top recruit of the Gophers, transferred to Rutgers in January after starting 16 games at Minnesota in 2012 and 2013. He participated in spring football practice at Rutgers, which is joining the Big Ten beginning this fall, but will have to sit out one season as a transfer student.

A football player at Minnesota State-Mankato, Kolstad started 12 games at linebacker as a senior in 2013 and was named to the all-Northern Sun Conference team.

Both Nelson and Kolstad went to high school in Mankato. Kolstad attended Mankato East; Nelson went to Mankato West. In high school, Nelson was named Minnesota's Mr. Football and was the Associated Press Minnesota football player of the year as a senior.

A Rutgers athletic department spokesman, Jason Baum, said in a statement that the school is "in the process of gathering information on the situation and reserve comment until the legal process is complete,"  according to the Newark Star-Ledger's web site.

"It's an ongoing investigation and as more information becomes available we'll be releasing it," city spokeswoman Shelly Schulz told The Associated Press.