The pair snapped a pic at a rehab center in Georgia on Thursday -- with The Nature Boy bragging, "Look who popped in today! Sir Charles."
Of course, Ric's on the road to recovery after undergoing emergency surgery to address organ problems ... and is looking great considering he was in critical condition last month.
Unclear if Chuck just happened to be in the same facility -- he had hip replacement surgery last year -- or was there specifically to visit Naitch ... but the NBA legend looks like he's ready to drop sweat.
FYI, Barkley and Flair have known each other for decades ... cutting a promo for WCW together back in the day.