Sydney - Captain James Horwill and star back Kurtley Beale were ruled out of Australia's Tests next month against Scotland and Wales with injuries, coach Robbie Deans said on Monday.
Lock Horwill damaged his hamstring during the Reds' 13-12 Super Rugby win over the Brumbies on Saturday and scans on Monday revealed a muscle tear.
Deans said the injury will keep Horwill out of the Test against Scotland in Newcastle on June 5 and the following three-Test series with Wales.
Beale injured his shoulder playing for the Melbourne Rebels in their 66-24 loss to the Hurricanes in Wellington on Saturday and scans showed he would also play no part in next month's Tests.
Beale had been favoured to start at flyhalf for the Wallabies as the regular No 10 Quade Cooper continues to work his way back from a long spell out with a knee injury.
"Kurtley had an appointment this morning with a specialist. He's going to require an operation," Deans said.
He added that the full extent of the damage to Beale's shoulder would not be known until after surgery.
"But the fact that he needs an operation is indicative that it is serious and it will rule him out of the June (Test) window," Deans said.
The coach said Horwill's injury was not as serious as he first feared.
"James, we are presuming, is out for the whole of June, but it is not as bad as it first looked. It looked pretty sinister at the time," Deans said.
Deans said he was not ready yet to announce his replacement captain, but flank David Pocock and scrumhalf Will Genia are considered front-runners to take the role against Scotland.