Former NBA center Jason Collins -- the league's first openly gay player -- has been diagnosed with a brain tumor and is currently undergoing treatment.
The league released a statement on Thursday on behalf of Collins and his family ... calling on his fans to send positive vibes his way as he deals with the medical condition.
"Jason and his family welcome your support and prayers and kindly ask for privacy as they dedicate their attention to Jason's health and well-being," the NBA said.