6:12 AM PT -- 12/12 -- A spokesperson for the Spinks family gave TMZ Sports a statement, saying ... "Leon is currently hospitalized and in the care of an exceptional team of doctors. We kindly request that privacy be given to his family at this time."
"His wife Brenda and their family would like to graciously thank all of Leon's friends and fans for all of the outpouring support of love and prayers."
Boxing legend Leon Spinks -- who famously beat Muhammad Aliin 1978 -- is fighting for his life in a Vegas hospital, TMZ Sports has learned ... and his wife is asking for prayers.
Details surrounding the 66-year-old's condition are unclear -- but we know his family and friends are very concerned.
In fact, Leon's wife, Brenda, went to social media saying, "Reaching out to ask you to kindly send some prayers out for my Beautiful Husband Leon so that he may overcome the obstacles that have crossed his path."