The hottest ticket in San Juan tonight will be a seat at Coliseo Jose Miguel Agrelot as WBO light fly ruler Ivan Calderon and WBO super feather supremo Roman Martinez put their crowns at risk.
Calderon, 32-0-1 (6), hasn't had a non-title bout in over five years after defending the WBO minimumweight trophy 11 times and his current WBO light fly belt on four occasions.
The 34 year old southpaw rematches big punching Filipino Rodel Mayo, 25-3-1 (19), a former OPBF minimumweight titlist who engaged in a six round TD with Calderon in Madison Square Garden in June when the Puerto Rican hero was cut too badly to continue.
Chief support in San Juan is provided by Roman "Rocky" Martinez, 22-0-1 (13), who makes the first defense of the WBO 130 lb belt he took off England's Nicky Cook in March.
Challenging Martinez is WBA Fedelatin feather strapholder Feider Viloria, 22-4-1 (15), of Colombia.
Bantamweight prospect Juan Mercedes, 23-2 (16), is also on the bill, meeting durable Florida veteran Robert DaLuz, 12-20-3 (9), over ten frames.