Sources -- Naoya Inoue-Marlon Tapales title bout in the works - ESPN

An undisputed junior featherweight championship fight between Japanese star Naoya Inoue and Marlon Tapales is being planned for Dec. 26 in Tokyo, sources confirmed to ESPN.

Tapales' manager, Sean Gibbons, said Thursday at the WBO convention in Punta Cana, Dominican Republic, that the plan calls for the Filipino to put his IBF and WBA titles on the line against Inoue, the holder of the WBC and WBO titles at 122 pounds.

Inoue, ESPN's No. 2 pound-for-pound boxer, moved up to 122 pounds in July and scored a dominant eight-round TKO of Stephen Fulton to win a title in a fourth division. «The Monster» welcomed Tapales into the ring afterward, setting the stage for Inoue to vie for another undisputed championship.

Inoue, 30, stopped Paul Butler in the penultimate round of their fight last December for the undisputed championship at 118 pounds. Inoue (25-0, 22 KOs) has also claimed titles at 108 and 115 pounds.

Tapales (37-3, 19 KOs) figures to enter the ring a heavy underdog. The 31-year-old southpaw upset Murodjon Akhmadaliev via split decision in April to become unified champion at 122 pounds, just like Inoue. Tapales also was a titleholder at 118 pounds.