As prosecutors prepare to try former New England Patriots tight end Aaron Hernandez on murder and gun charges, new details have emerged about a 2007 bar fight at the University of Florida that suggest the incident was far from trivial.

According to a 2007 police report obtained Monday by The Wall Street Journal, Hernandez had a brush with the law at Florida before he'd even played a down.

On May 4, 2007, only months after Hernandez had enrolled at Florida, he showed up at a restaurant called The Swamp near Florida's campus in Gainesville, Fla., a two-story bar and grill that features framed jerseys of former Florida stars.

According to the police report, here's what took place: A waitress brought Hernandez two "alcoholic drinks." After Hernandez finished the drinks, a restaurant employee named Michael Taphorn delivered a bill. Hernandez said he hadn't ordered the drinks and refused to pay, at which point a "verbal altercation" began between the two men. Hernandez called a witness over to try to intervene, but a resolution couldn't be reached. Hernandez was told to leave and escorted out by Taphorn.

After stepping outside, according to the report, Hernandez told police Taphorn "got in his face" and began yelling at him. As Taphorn turned to walk away, Hernandez punched him in the side of the head—a fact Hernandez did not dispute.

Taphorn complained of hearing loss in his ear but refused medical treatment on the scene, the report said. The next day, however, doctors discovered his right eardrum had burst, an injury he was told would take four to six weeks to heal, according to the police report.

Benjamin Tobias, a spokesman for the Gainesville police department, said officers did not arrest Hernandez, who was 17 at the time. But given the severity of the injury to the victim, the department recommended a charge of felony battery—a crime that, for adults in Florida, carries a maximum of up to five years in prison.

Hernandez's attorney, Michael Fee, did not return emails and calls for comment. Former Florida football coach Urban Meyer, now the head football coach at Ohio State, has declined to comment on Hernandez.

Taphorn, whom colleagues described Monday as a former manager at the restaurant, could not be reached for comment. Danny Zeenberg, manager at The Swamp, said the restaurant does not serve alcohol to underage customers.