A bat boy for a Kansas amateur baseball team died over the weekend after being struck by a player in a tragic accident, according to an ABC report.

Kaiser Carlile, 9, the sole bat boy for the Liberal Bee Jays summer team died on Sunday, a day after being accidentally struck by an unidentified Bee Jays player during a National Baseball Congress World Series game against the San Diego Waves in Wichita, Kansas.

Not noticing Kaiser, the player, who was taking practice swings near the on-deck circle, reportedly struck him as the boy was running toward home plate to retrieve a bat.

The follow-through warm-up swing reportedly hit the 9-year-old on the head.

Despite wearing a mandatory helmet, Kaiser suffered severe head injuries and was hospitalized in critical condition, before eventually succumbing to the injury on Sunday evening.

Tributes for Kaiser, a self-proclaimed Bee Jays "superfan", came pouring in through social media, including from team member Kadon Simmons who, in a post to Instagram called Kaiser the "little brother [he] never had."

"No person or team could ask for a better bat boy," wrote Simmons. "It is terrible to see you leave in such a way, but knowing your last moments were on the baseball field makes it easier through this whole process, because you were doing what you loved."

Saying it was what Kaiser would've wanted, the Bee Jays opted to continue playing the game and won 12-5 in 13 innings.