John Salley says the mother of the NBA G League player who died after collapsing on the court is "100% right" in her lawsuit against the league ... saying, "I think she has a case."
TMZ Sports broke story ... Zeke Upshaw's mother claims the team doctor didn't respond to her son for 4 MINUTES after he collapsed from a cardiac incident during a game back in March.
Upshaw's mother claims Zeke did not receive proper medical treatment that could have saved his life, and she's holding the Detroit Pistons and the NBA responsible.