Toronto Raptors guard RJ Barrett is breaking his silence on his little brother's death ... saying Nathan's passing is "a lot tougher" than any other loss he's experienced in his life.
The NBA player was emotional when he spoke about his late 19-year-old brother with reporters at Friday's practice ... his first time rejoining the Raptors since the family tragedy.
"I’ve had some people in my life, but this one hit a little harder for me," Barrett said.
"This one is definitely a little different, it’s a lot tougher, and I just think that you’ve gotta push forward every day, gotta be able to try to figure it out."
The Barrett family released a statement earlier this month ... saying Nathan was surrounded by family members and loved ones at the time of his death, although additional details have not been made public.
Nathan was also an athlete -- he followed in his brother's footsteps by playing basketball at Montverde Academy. However, he changed course and was pursuing a career as a pilot.
"If I know my brother, he would want me to be here, to be playing," Barrett added, "to try to continue to make the Barrett legacy grow."
Barrett -- who was traded to the Raptors in December -- has not played since March 11 ... and will make his return to the court against the 76ers on Sunday.