Hours before the fighters competing on Saturday’s UFC Rio event are scheduled to officially weigh-in, the fight card lost one of its bouts. A heavyweight clash between the brothers of former welterweight champion  Kamaru Usman and light heavyweight contender  Johnny Walker , Mohammed Usman and Valter Walker, was suddenly cancelled after Usman withdrew for undisclosed reasons. Usman (11-4) won The Ultimate Fighter 30 Heavyweight Tournament in 2022.