Ja Morantis as ruthless as he is athletic -- the Grizzlies star savagely mean-mugged a kid in a Warriors jersey during Memphis' game Tuesday night ... but he's at least now apologizing for the cold shoulder.
In the fourth quarter of the Grizzlies' game against Golden State ... Morant took over, and hit a huge clutch bucket to extend Memphis' lead.
Ja Morant on the kid with the Steph jersey 😂
"He was disrespectful with that jersey on. We in Memphis. It looked like he wanted to cheer but he had that jersey on. I apologized to him but in that moment, bro, take that jersey off and then dap me up." pic.twitter.com/t5NFzc2jcq