Napoleon McCallum -- the ex-Raiders running back who nearly lost his leg after suffering a devastating knee injury during a game in 1994 -- is advising Nick Chubb to consider all of his options before coming back to the football field full-time.
The former Oakland tailback tells TMZ Sports ... if he had the chance to sit and talk with the Cleveland star following the 27-year-old's injury last Monday night -- he'd be sure to get that message across to him.
"I understand it's hard to leave," McCallum said of what he'd say to Chubb.