MANKATO – Five to 10 seconds.

That's how long police say an altercation, likely exacerbated by alcohol, lasted early Sunday as bars closed in downtown Mankato.

Now, a 24-year-old father is in grave condition with a fractured skull and swollen brain. Doctors are unsure if Isaac Kolstad will survive and, if so, the extent of the brain damage he suffered.

Former University of Minnesota starting quarterback Philip Nelson, 20, stands charged with first- and third-degree assault, facing up to 20 years in prison for allegedly kicking Kolstad in the head.

And police are searching for a third man in his 20s wearing a torn red shirt, seen on city surveillance cameras delivering a punch that witnesses say seemed to knock out Kolstad before his head crashed loudly against the street and Nelson allegedly kicked the left side of his skull "like a soccer ball."

"You have some decisions that were made by some individuals that probably had some impaired thinking and those decisions will affect many lives for years to come," said Patrick McDermott, assistant Blue Earth County attorney.

Nelson, a high school football star from Mankato who transferred to Rutgers University after last season, appeared in court for 10 minutes Monday wearing orange jail fatigues.

His wrists were handcuffed and his feet were shackled as his parents looked on.

He was released on $20,000 bail a few hours later. He agreed to make all court appearances and waive extradition so he can return to school in New Jersey and attend a family graduation in Wisconsin as his case begins to unfold.

Blue Earth District County Judge Bradley Walker said he based the bail amount on guidelines for offenders with no criminal history.

Nelson "was not the aggressor in this situation," his attorney, Jim Fleming, told the judge. "The man in the red shirt rendered the young man unconscious."

Police released video from some of the city's 140 surveillance cameras, seeking the public's help in identifying the man in the red shirt who dashed away. They were also asking for help from other witnesses seen on the videotape.

"The entire thing lasted five to 10 seconds," said Todd Miller, Mankato's public safety director. "Mr. Nelson and Mr. Kolstad know each other and played football against each other in Mankato in high school."

According to the criminal complaint, there were several versions of what happened at the intersection of Cherry and Front streets about 2 a.m. Sunday.

But the dispute seemed to start when a bouncer at the Blue Bricks bar kissed Nelson's girlfriend's hand, prompting him to get irate and possibly confuse Kolstad for the bouncer when they were later out on the street.

Nelson and his girlfriend told police there was no kick to the head. But the complaint includes an account from Mankato police Sgt. Jeff Knutson, who reviewed footage from the city's cameras. He said Kolstad seemed to trigger things when he "raised his arm and struck Nelson in the back area with the punch."

That knocked Nelson and another witness to the ground. Kolstad moved away when the suspect being sought in the red shirt broke free from another man restraining him and ran toward Kolstad.

"The unknown suspect delivered a punch to the face/head area of [Kolstad, who] immediately goes limp and collapses to the pavement," the complaint said.

The sergeant then said the video shows Nelson pushing past others "and delivers at least one kick to the left side of [Kolstad's] head." Kolstad was clearly defenseless when he was kicked, the complaint says.

Two witnesses told the Star Tribune they saw the entire altercation after leaving separate bars.

"All of a sudden, this guy comes out of nowhere and sucker punches," said Steph Stassen, 25, a graduate student who was celebrating her graduation with her roommate and first ran to get police.

"He [Kolstad] was knocked out on his feet," Stassen said. "He fell straight back and smoked his head on the pavement."

She said "the noise of him hitting his head was so loud."

"He didn't try to brace himself or catch himself," Stassen said.

A man she later learned was Nelson then kicked him once in the head "like it was a soccer ball — just out of nowhere."

She said everyone was in shock about what had just happened and she ran to get a police officer she had seen minutes earlier. An ambulance arrived about five minutes later.

"He was unconscious after the first punch," said Stassen's roommate, Mackenzie Skay.

Kolstad's family asked for privacy Monday from his bedside at a Mayo Clinic facility in Mankato. They thanked the more than 25,000 well-wishers praying for him through a CaringBridge website.

"We also extend our sincere thoughts and prayers to the Nelson family and others whose lives have been impacted by this situation," Kolstad's family said through a Mayo spokesman.

"Please keep in mind that behind the headlines — behind the police reports and the medical data — is a strong, caring man … a loving husband, a father of two daughters …"

Todd Hoffner, head coach at Minnesota State University, Mankato, where Kolstad was a highly respected linebacker, visited the hospital. "All our thoughts and prayers go out for Isaac and a full recovery," Hoffner said.

But a neurosurgeon quoted in the complaint said Kolstad was suffering from "a severe head injury and a severe pulmonary injury" and he's not sure if Kolstad will survive.

If he does, Dr. Dominic Cannella is "not optimistic that he will make a good recovery," according to the complaint. "They were taking the situation hour by hour."

Curt Brown • 612-673-4767