WBC president Mauricio Sulaiman has said Ring, IBF, WBA, and WBC heavyweight champion Oleksandr Usyk must defend his titles the German, their interim beltholder, after a voluntary defense.

Kabayel has been in possession of interim belt since stopping Zhilei Zhang in the sixth round a year ago.

Kabayel has waited patiently for his opportunity and was last in action against Damian Knyba, stopping him in the third round on January 10. Usyk hasn't fought since last July when he stopped Daniel Dubois and has been nursing a back injury since.

“Kabayel was not available because he had a fight scheduled in January,” Sulaiman told Chris Mannix. “So [Usyk] requested a voluntary title defense which is very customary. He was given that opportunity and he must fight the interim champion next. That’s the ruling.”

It remains to be seen who Usyk will take on next after originally sought-after opponent Deontay Wilder elected for a clash with Derek Chisora instead.

One thing's for sure; after Usyk fights his voluntary it's Kabayel or vacate.