Speaking with Sherdog.com, promoter Monte Cox announced the six-round heavyweight fight would be rescheduled for June 13 in Alabama as the main event of Adrenaline III. The hybrid boxing-mixed martial arts event will be held at the 17,000-seat BJCC arena in Birmingham.
Cox confirmed that Alabama does not have a regulatory body to oversee the fight.
Sylvia, 33, a former UFC heavyweight champion, will be making his professional boxing debut against the 1988 Olympic gold medalist.
Mercer, who piled up a 36-7-1 record over his 20-year boxing career, is a former WBO heavyweight champion who has also fought in K-1 as well as dabbling in MMA. The 47-year-old dropped his only MMA match, a bout sanctioned as an exhibition in New Jersey, to Kevin “Kimbo Slice” Ferguson.