SYDNEY • Australia's Olympic hopes were dented yesterday, as road cyclist Simon Gerrans withdrew from the Rio Games with an injury while Lleyton Hewitt was set to pull out as tennis coach.

Gerrans, 36, who was due to ride in his third Games, had to quit the Tour de France on Thursday after breaking his collarbone in a crash and later had surgery in Spain.

"With my current injury, my (Olympics) preparation would be seriously jeopardised, and so too my performance at the Games," he wrote in a letter to team officials. "For Australia to have the best chance to achieve the best result possible, I feel I should be replaced by one of the riders in the squad."

Cycling Australia will select a replacement this week, the Australian Olympic Committee (AOC) said. Also in the men's road cycling team are London 2012 track silver medallist Rohan Dennis and Richie Porte, a regular Grand Tour contender. A fourth rider has yet to be named.

Separately, Tennis Australia has applied to the AOC to replace Hewitt with Mark Draper as coach at the Games. No explanation was given but the Sydney Morning Herald reported that the 35-year-old former world No. 1's withdrawal was owing to "personal reasons".

The news is a setback for the tennis team, with troubled stars Bernard Tomic and Nick Kyrgios already missing from the line-up after withdrawing from the Games.

In better news, rising Australian star Jordan Thompson has won a late call-up to contest the men's singles alongside countrymen Thanasi Kokkinakis and John Millman.

Thompson advanced to the second round of the French Open before losing 10-12 in the fifth set to Croatian stalwart Ivo Karlovic, helping to lift the Australian's world ranking to a career-high of 88.

With Wimbledon runner-up Milos Raonic also joining the list of Rio withdrawals on Friday - in part due to fears over the Zika virus - a spot opened up for the 22-year-old Thompson.

AGENCE FRANCE-PRESSE, THE GUARDIAN