Ice Cube's BIG3 league is missing out on a major ex-NBA talent who says the league needs to give him a look ASAP ... like YESTERDAY, because he's SURE he has enough game left to compete.
The man is Isaiah Rider ... who averaged 16.7 ppg over 9 NBA seasons -- a serious player -- and told us he feels like he's not getting a fair shake at continuing his hoops legacy in the BIG3.
"I been in the draft the last three years ... They know I'm available, it's a buddy league.