ESPN's senior boxing writer Dan Rafael is reporting that the World Boxing Organisation have agreed that Parker and Ruiz Jnr will fight for the title left vacant by Tyson Fury.
The WBO were having a five-day convention in San Juan, Puerto Rico to discuss how to decide on a title fight.
The promoters of both Parker and Ruiz Jr all but agreed terms and the fight is set to take place in New Zealand on December 10.
Parker, No 1 with the WBO, has first rights to challenge for the title in the wake of Fury's decision to step away from boxing due to health reasons.
The WBO had raised the spectre of a four-way box-off, with Anthony Joshua and Wladimir Klitschko the other pair in the mix but according to ESPN they have agreed to a Parker-Ruiz Jr fight instead.
