Rossel, the #1 ranked fighter and the current interim world champion of the WBA, has apparently got his next bout scheduled for March 8th though with Petalcorin himself busy around the same time this bout would have to be made around the summer.
Representatives for Petalcorin has suggest that the winner would be the ideal candidate to fight Kazuto Ioka (14-0, 9) later this year in a WBA mandatory title fight and a WBA title unification.
A related story coming out of Japan is that Ioka will be seeking to unify titles in May before making a defense of the unified titles later in the year
Reading between the lines it would suggest that Ioka would be able to fit in a title defense in the fall with the winner of the Petalcorin/Rossel bout before moving to Flyweight in an attempt to become a 3-weight world champion in December.
Of course these negotiations are all in early stages and it wouldn't be a big surprise if Rossel is removed completely from the equation, if Ioka cannot secure a unification bout and instead he fights Petalcorin in May, as long as Petalcorin quickly takes care of Lookrak Kiatmungmee on March 28th.