The 17-year-old was booked into a juvenile detention center on suspicion of aggravated assault, said Unified Police Lt. Justin Hoyal. Those charges could be amplified if the 46-year-old referee's condition worsens.
The incident happened in a flash during a soccer game Saturday at Eisenhower Junior High School in Taylorsville, a Salt Lake City suburb.
The referee called a foul on the player and issued him a yellow card, triggering the player to turn and punch him, authorities said. At first, it appeared the referee just had minor injuries.
When the man was taken to a hospital, however, they discovered serious internal head injuries, Hoyal said. He's been in critical condition since Saturday.
There was no buildup to the incident, or previous exchange of words between the referee and the player, Hoyal said.
"It was almost an instinctive reaction," Hoyal said.
By the time police arrived to the field Saturday, the teenager had left. Police investigated the incident over the weekend and arrested the teenager Monday. He is in the Salt Lake Valley Juvenile Detention Center. His name isn't being released because he's a minor.
The referee's name also was withheld.
The game was part of a "rogue league" unaffiliated with the popular Utah Youth Soccer Association or any city or town recreation department, association CEO Andrew Hiatt said. The association has 50,000 youth players and 15,000 coaches statewide.
The man did not appear to be a licensed referee.
In the state association, any player or coach that puts a finger on a referee faces immediate suspension. Players and coaches also sign a code of ethics.
"To see something like this is not what we are looking for," Hiatt said. "It's horrible. Hopefully we use this as teaching moment to continue to push sportsmanship."
This isn't the first time an athlete has hurt a referee.
In December, a 41-year-old Dutch man working as a linesman in youth soccer game in the Netherlands died after he was kicked and beaten by a group of players aged 15 and 16. Three teenagers were arrested on suspicion of manslaughter, and four more were later detained on suspicion of involvement in the attack.
Youth players are mimicking what they see from parents and professional players who often fail to control their emotions and berate referees, said EJ Reyes, president of the Taylorsville Youth Soccer League, one of 46 clubs statewide affiliated with the Utah Youth Soccer Association.
Reyes recently took a group of his players to a Real Salt Lake reserve league game in which a fight broke out. It set an awful example for the impressionable kids who saw it close-up, he said.
Reyes noted parents increasingly are becoming disrespectful toward referees, as well.
"The kids are reciprocating what they see," Reyes said.