Former heavyweight champion Wladimir Klitschko has suffered an injury and will not fight IBF titleholder Anthony Joshua in December.

Klitschko had been trying to retain the IBF and WBA title before the end of the year, but ESPN reports the Ukrainian has injured his calf.

Both camps were awaiting notification from the WBA on whether it would sanction a fight after Tyson Fury vacated the title due to mental health problems.

It's thought the fight will be rescheduled for early next year.