(CNN) -- A Maryland man severely injured in an alleged assault at a Baltimore Orioles baseball game was revived by an off-duty state trooper at the scene who apparently didn't know immediately the victim was a childhood friend. Nathan Steelman was seated a few sections away on Wednesday night at Camden Yards when Matthew Fortese, 25, was punched in the side of the head during an apparent argument with two other men and fell off a wall, police records show. His head hit the pavement below with a loud thump. The incident apparently was triggered when the men sitting in the section behind Fortese apparently taunted him about his New York Yankees hat and threw beer on him, his brother, James, said. Fortese was not breathing and was bleeding badly from behind his head when Steelman reached him. Steelman pried open his mouth and cleared his airway, allowing Fortese to breathe on his own, Steelman said. It wasn't until later that Steelman realized he had known Fortese for years. "I think instinct kind of kicked in," Steelman told CNN on Friday. "I didn't know it was Matt at the time." "I grew up with him playing baseball together," Steelman said. Fortese remains in intensive care in stable condition with a fractured skull at Maryland Shock Trauma Center, James Fortese said. "He's not confrontational," his brother told CNN. "He was just trying to enjoy the game." Two men were charged in the incident and were held on $50,000 bond, authorities said. Orioles spokesman Greg Bader confirmed the team was aware of the incident but had no further comment. In 2012: Two California men plead not guilty in beating of Giants fan .
Man severely injured in altercation with two fans at Baltimore baseball game . Off-duty trooper who performed first aid on victim realized later two were old friends . Two men held in alleged assault . Victim hospitalized in stable condition with head injury .