An 11-year-old footballer was shot in the forehead with an air weapon as he waited on the pitchside to play, police said.
Connor Minto needed stitches to remove the pellet from about an inch above his left eye and suffered what a detective said was a "nasty" injury.
He was a subsitute for an under 12s game between Chester-le-Street Town and Coxhoe in a match played at the Hermitage Academy on Saturday lunchtime.
The pellet was removed at Newcastle's Royal Victoria Infirmary (RVI) and police said his injuries could have been much worse.
Three boys aged 14 from the Chester-le-Street area have been arrested in connection with the incident and were bailed pending further investigations.
Detective Constable Andy Froggatt said: "Connor was standing next to the nets with some other boys watching a nearby rugby game when he felt what he thought was a stone hit his head.
"He ran to his dad because he could feel blood and his dad could see that a .22 pellet was lodged in Connor's forehead just above his left eye.
"This was a very serious incident.
"The photos clearly show how nasty the injury was, but it could have been much worse if the pellet had hit Connor's eye.
"His dad took him to the RVI hospital where the pellet was removed and he received stitches. Thankfully Connor is recovering well now, but he was extremely upset by what h
"We are appealing to anyone who was at the football or rugby games that were being played on Saturday and witnessed the incident to contact police.
"We'd also like to remind people about the dangers of using air weapons in public places.
"If anyone needs any advice on this subject, particularly in relation to the laws around children using air weapons, please contact police."