By Duncan Johnstone

Joseph Parker's world title prospects have increased with the WBO putting heat on Tyson Fury to explain his medical condition.

Fury pulled out of his defence of the WBO, IBO and WBA titles in a rematch with Wladimir Klitschko, citing mental health issues.

The WBO have given him 10 days to produce medical proof, raising the prospects of him being stripped of that title. Parker is ranked No 1 with the WBO and is also the mandatory challenger to the IBF belt held by Britain's Anthony Joshua.

Suddenly the 24-year-old Kiwi finds himself in the driver's seat for challenges to two of the coveted belts, if Fury loses that WBO title.

Parker fights Russian Alexander Dimitrenko in Manukau on Saturday night, a risky fight given everything on his horizon, but one his handlers feel he needs to negotiate, given his opponent's size - and the bigger yet challenges ahead.

"So long as Joseph Parker wins on Saturday night, he is locked into the best position of any heavyweight in the world with the exception of Anthony Joshua himself," claimed Parker's promoter Dean Lonergan on Wednesday as news broke of the WBO's toughening stance against Fury.

Lonergan's logic suggests that if Parker doesn't fight Joshua on November 26 as the mandatory challenger there's the prospect of lining up a shot against Klitschko or Andy Ruiz for the vacant WBO belt if Fury is stripped.

"Joe is perfectly positioned, it's a fascinating time."

The WBO's threatening letter to Fury read: "We would appreciate that the physician specifically clarifies the nature and extent of your condition and your prognosis for return to training and your return to competition.

"If the Championship Committee does not receive the complete requested information, i.e. the Interim Certification, together with the Psychological and/or Mental Evaluation, within the allotted time frame of 10 days, the Committee will proceed with the necessary appropriate action without the benefit of an appeal."

Joshua's manager Eddie Hearn continues to work towards a November 26 showdown with Klitschko in Manchester with the prospect of the WBA belt being added to the booty.

Just how that works when Cuban Luis Ortiz is the WBA No 1 ahead of Klitschko and Joshua isn't even ranked in the organisation's top 15 is another mystery of a cluttered boxing scene.

But Hearn feels the Klitschko deal is workable, telling Boxingnewsonline.com "things are moving at a very, very quick pace".

"He [Joshua] wants the [Klitschko] fight. He wants to fight everybody, he wants to fight Fury, he wants to fight David Haye. The training team will make their mind up and he'll do what the training team say. But the training team say the deal is right and the belts are on the line, we'll take the fight. So it's my job now to make sure the deal is right and everything else falls into place," Hearn said.

"The governing bodies aren't going to sleep on this situation. They want the belts to be active as soon as possible."

Hearn has Parker as the fallback option if the Klitschko deal can't be made quickly. The Kiwi's mandatory would be called, making him the main event for Manchester rather than an undercard role.