Grizzlies star Ja Morant is sharing his side of the altercation at his sister's volleyball game that led to a police investigation ... saying he only showed up to the event to make sure she was safe.
TMZ Sports broke the story -- Morant, his family and a group of adult men were investigated for simple assault in September ... after they were accused of confronting a high schooler who allegedly called his sister a "bitch."
Morant was asked about the incident in an interview with ESPN's Jalen Rose on Wednesday .