A boy was left with a fractured skull and brain damage when he was accidentally hit by a stray throw at a professional baseball game.

Bryson Galaz, aged six, was struck during a warmup when Los Angeles Angels pitcher Keynan Middleton threw a ball to a teammate, who missed the catch.

The child’s mother has launched a lawsuit against the Angels over the 2019 incident, saying that her son is now “simply not the same”.

Bryson was walking with his father in the first row of stadium seating toward the dugout when he was hit by the ball, the lawsuit said.

At the time, players were meeting fans and signing autographs more than an hour-and-a-half before the start of the game at Angel Stadium in Anaheim, California.

He was taken to hospital in a critical condition after sustaining a fractured skull and brain damage and had to be monitored for nearly three days.

Bryson now has difficulty paying attention and with social interaction, says family lawyer Kyle Scott.

Medical exams have also shown abnormal brain activity, raising fears over his long-term development.

“We’re grateful that he pulled through, but since that day he has struggled in school,” said his mother Beatrice Galaz.

Mrs Galaz says the Los Angeles Angels should have more netting along the side of the field and players shouldn’t throw balls during warm-ups.

“This is not about putting kids in a bubble or ensuring the safety of everybody that comes to the ballpark,” said Keith Bruno, another lawyer for the family.

“This is about taking common-sense measures and protecting the most vulnerable that we have from known dangers.”

After the incident, Middleton, who is not the target of the lawsuit, went over the check on Bryson, and stadium officials called for help.

Mr Scott said the team followed up with the family via email but did not reply when asked for help with medical bills.

The lawsuit seeks unspecified damages and coverage of medical costs and loss of future earnings.

The Los Angeles Angels declined to comment on the litigation.

“No parties have reached out to us regarding this lawsuit,” Angels spokesperson Marie Garvey told Associated Press.

“We have only been made aware of this by the media, so we are unable to comment at this time.”