Lakers guards are turning over women like they do basketballs ... first Nick and Iggy, now D'Angelo Russell is on the market ... after a breakup with his superstar college athlete GF Niki Withers.

The couple scrubbed each other off all social media -- a telltale sign of trouble in paradise -- and sources close to the situation confirmed the two are, in fact, dunzo.

"D'Angelo and Niki talked about where the relationship was going and decided mutually to break up," one source tells us.

Unlike Nick & Iggy there's no bad blood between the two ... we're told the breakup was simply a case of two youngsters growing apart.

The relationship endured some tough times ... with Niki standing by DR when his infamous video of Swaggy made him the number one bro code violator in the history of sports.

Question is, now that both men are single ... might it be time to reignite the friendship over a few thots?