I gotta say, I don't believe Brock's excuse. He went back to MMA after diverticulitis. Then he went to the WWE, which is also hard on the body. That doesn't sound like someone who is il.
The briefness of his stint in the UFC stinks of Ronda, Conor, Paige, and Gina Carano. They start to lose MMA fights, and suddenly they're all over the place dancing, boxing, acting, fake retiring, crying on couches, and running around in a ring with makeup on acting like clowns. That's their right, but as an MMA fan, fuck them.