Youth Basketball Player Stomps On Opponent's Head, Police Investigating

A 13-year-old basketball player viciously stomped on his opponent's head in the middle of a game over the weekend ... and now, the whole incident is under police investigation.

It all went down during a matchup between Payton's Place and Tumakbo United organizations at the College of Alameda in California on Sunday ... when the players were battling for possession of the ball.

During the action, a 13-year-old athlete for Tumakbo United fell to the ground as he tried to maintain control over a defender ... when out of nowhere, another Payton's Place player got involved and forcefully used his foot to put the kid's head to the hardwood.

A referee quickly wrapped his arms around the Payton's Place player ... and a coach joined in to help whisk him away to the sidelines.

The mother of the player whose head was stomped on said her son suffered a concussion as a result ... telling ABC 7, "You could clearly see the size of his shoe on his face."

The family of the kid who did the stomping said he was simply standing up for his teammate ... who he believed was punched and kicked in the scrap prior to his involvement.

Tumakbo United is a Filipino-American team comprised of players throughout the country ... although coaches told the outlet they do not believe race played a factor in the incident.

The family of the kid whose head was stomped has since filed a police report ... and an investigation is underway.

Payton's Place released an apology over the matter ... saying, "The behavior that was exhibited by our player is not acceptable, and is being taken seriously. We do not condone violence."

"Our players are expected to conduct themselves with integrity on and off the court. At this time, both teams are working together to resolve this matter."