A nine-year-old who spent the summer working as bat boy for Kansas collegiate baseball team the Liberal Bee Jays died Sunday evening, one day after he was hit in the head by a warmup swing during a National Baseball Congress World Series game.

Kaiser Carlile reportedly ran onto the field to retrieve a bat and was struck by a player taking a practice swing. Witnesses said they heard the bat hit Carlile, who was wearing a helmet, and watched as he fell over, stood up, and then fell again. From KSN:

According to witness Jim Parks, the incident took place after one of the Bee Jay’s batters had struck out and the batter on deck was taking practice swings.

Parks said Kaiser Carlile, the bat boy and a Bee Jays superfan, was running to pick up a bat on the ground when the on-deck batter took a practice swing and accidentally hit the boy in the head.

“He was swinging, and it hit him in the helmet, knocked him down, he got back up, but he went right back down again,” said Parks.

“Just to see him fall, that’s what crushes you,” team president Nathan McCaffrey told CNN after confirming the boy’s death.

The home plate umpire, who also works as a firefighter and paramedic, performed CPR on the boy until an ambulance arrived. Carlile was rushed to the Intensive Care Unit at Via Christi St. Francis hospital in Wichita, where he died Sunday evening.

Members of the Bee Jays paid tribute to their nine-year-old teammate—who was set to begin fourth grade later this month—last night.

Contact the author at taylor@gawker.com.