Egis Klimas, manager of former undisputed cruiserweight champion Oleksandr Usyk, says his client is still watching very closely to see if Tyson Fury vs. Anthony Joshua locks down a date and venue.

Fury and Joshua signed on for a two-fight series, with the first bout being targeted to land in June or July.

Their heavyweight unification will have the WBO, IBF, IBO, WBC, WBA world titles at stake.

Usyk is the WBO's mandatory challenger to Joshua.

The Olympic gold medal winner returned to the ring back in October, when he won a tough twelve round unanimous decision over Dereck Chisora. The scores were 115-113, 117-112 and 115-113.

The World Boxing Organization has approved the scenario of Usyk facing number two rated Joe Joyce in a clash for the WBO interim-title - with the winner landing a mandatory crack at the victor of Fury vs. Joshua.

Because Fury-Joshua has an immediate rematch clause, regardless of the winner, it's very likely that Usyk or Joyce would be elevated to the position of full champion by the WBO.

If Fury-Joshua fails to find a venue in the coming weeks, the fight would fall apart and the WBO could potentially order Joshua to make his mandatory defense against Usyk.

"At the moment everything depends on the WBO. Joshua and Fury seem to have agreed between themselves, but there is no location and date. Oleksandr is the mandatory challenger for the WBO title. If they do not finalize the details or there is no date, the sanctioning body is obligated to order Usyk a fight with Joshua. If the WBO tells Joshua to box with Usyk, it won't be for a vacant title [like the fight with Joyce], there would be four titles at stake," Klimas said in an interview with Usachev TV.