French heavyweight Tony Yoka has been ruled out of his WBA "regular" title clash with Murat Gassiev due to injury, sources have told ESPN.
Yoka was set to face Gassiev in Moscow on July 11 for Gassiev's title but has been forced to pull out having sustained a back injury.
Brit Joe Joyce, who is set to fight on the undercard in Moscow, is a potential replacement for Yoka, sources told ESPN
Oleksandr Usyk was the full WBA champion at heavyweight until he vacated all his titles last month. The clash between Yoka and Gassiev was shaping up as a crucial one in the division.
Yoka's withdrawal comes after his scheduled bout with Lawrence Okolie was canceled in April after Okolie returned an adverse drug test.
