Aussie Olympic tennis hope Millman injured

Australian Olympic officials are scrambling to contact tennis hope John Millman after his injury-enforced withdrawal from a Canadian tournament.

Millman is Australia's top-ranked player at the Rio Olympics, after Nick Kyrgios and Bernard Tomic pulled out.

But just a week before the Games, the world No.67 was forced to retire because of an injured wrist during his first-round clash against American Jared Donaldson at an ATP event in Toronto.

Australia's Olympic chef de mission Kitty Chiller says she's unaware of the extent of Millman's injury.

"We haven't been able to get an update on Millman yet," Chiller said on Thursday, citing time differences between Brazil and Canada.

Millman heads a three-man Australian tennis team at the Rio Olympics also including Thanasi Kokkinakis and Jordan Thompson.