Ex-NBA player Bo Kimble is pleading with Chris Bosh ... RETIRE IMMEDIATELY ... saying he doesn't want to see Bosh die on the court like his friend and college teammate Hank Gathers.
The Heat shut Bosh down on February 9th when the clotting issues that ended his '14-'15 season returned ... this time showing up in his calf.
Bosh is reportedly unhappy with the decision ... and feels he's healthy enough to resume his playing career.
Kimble -- who was present when Hank Gathers died during a college game in 1990 -- thinks returning to the league is a bad idea for Bosh.
"There are so many other things he could do with his life. Hank Gathers had the same thing, Hank could have been a comedian, and actor or did speaking engagements. It’s not worth the risk. I would just say absolutely not, don’t do it."
Gathers was aware of his heart ailment and decided to keep playing anyway ... and Bo says Chris has the chance to make a decision Gathers couldn't.
"If Hank had the ability to do it again he wouldn't have paid the ultimate price ... I am sure [Bosh] has children and they are going to need their father around as much as possible."
We also spoke to Hank's brother Derrick who echoed Kimble's sentiments.
"To this day I am just getting over the loss of my brother ... just fall back and retire."
FYI, We reached out to Dr. Oz to explain Bosh's condition and why it's so serious -- check out the video.