A boxing "superfight" of sorts between former UFC heavyweight champion Tim Sylvia and former WBO heavyweight boxing champion Ray Mercer has been struck from Adrenaline III on May 30 at the Taj Mahal Casino in Atlantic City, N.J.

Adrenaline promoter Monte Cox alerted MMAWeekly.com of the change late Monday evening.

The New Jersey State Athletic Control Board has refused to sanction the headlining bout, according to Commissioner Nick Lembo, though he declined to comment on the decision.

Adrenaline III will go on as an all-MMA card, and several replacements for the main event are under consideration, including Jeremy Horn.

Adrenaline promoter Monte Cox is currently searching for another venue to host the Sylvia-Mercer tilt, and indicated June as a possibility for the rescheduled event.

The bout with Mercer is to serve as Sylvia's professional boxing debut, having served an eight-year career in mixed martial arts that lead him to the pinnacle of the sport, twice serving as UFC heavyweight champion.

Mercer, 47, is 36-7-1 as a professional boxer, a gold medal winner in the 1988 Olympics and a former WBO heavyweight champion. Mercer dipped his toes into MMA waters in 2007 with an exhibition bout against Kevin "Kimbo Slice" Ferguson, losing by submission early in the first round. His last fight was a boxing match last September in Sweden, where he won a decision over Richel Hersisia.

The fight was originally under consideration as an MMA bout, but in earlier comments to MMAWeekly.com, Cox decided a boxing match would be more competitive.

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