A beloved teenage football player was "caught in the crossfire" during a violent pub brawl, but managed to walk to a nearby friend's home before he collapsed.

Patrick Cronin, 19, had never been in a fight before Saturday night, according to Lower Plenty Football Club president Grant Barden, who has known the boy's family for years.

The teenager suffered a critical head injury at The Windy Mile in Diamond Creek, on Melbourne's outer northern fringes, while trying to help out a friend.

"Patrick's never been in a fight in his life. He's not that kind of kid," he said.