We needed more certainty about his ability to handle the tough demands of our long season
Northampton Saints revealed on Monday that Wallaby veteran Cameron Shepherd has failed a fitness test and will not now be joining the club.
The 28-year-old Shepherd, who played nine Tests for Australia between 2006 and 2010, has been struggling with a succession of injuries in recent seasons.
He was due to arrive at the Saints in August, having signed a contract several months ago.
As is standard practice the contract was signed subject to a number of conditions, and, on the recommendation of their medical team, the Saints has decided to withdraw their offer to Shepherd.
"Obviously it is important to believe we will get the most out of our squad throughout the season," Saints Director of Rugby Jim Mallinder said.
"With a minimum of 32 games in Premiership Rugby, the European Cup and Anglo-Welsh Cup, our campaign is the most demanding in the world.
"We obviously monitored Cameron's condition between signing his contract and his scheduled arrival and after great consideration felt that on balance we needed more certainty about his ability to handle the tough demands of our long season for the duration of his three-year contract.
"We know Cameron has ability and are confident that he will be with another club soon.
"But while we are disappointed that Cameron will not be joining us we are nevertheless very confident in the ability of our squad to compete in every competition this coming season.
"We have welcomed some exciting players like Ken Pisi, Dom Waldouck, CJ Van Velze and Luther Burrell to Franklin's Gardens who can offer a great deal in a number of positions.
"They have settled in well, bonded with the rest of the squad and worked very hard in pre-season training and we are all looking forward to the start of the season."
Shepherd was born in England, but grew up in Sydney - playing basketball and rugby for Barker College.
He later signed with the Waratahs. In 2003 Shepherd represented Australia at Under-21 level and the following year he played for Australia A.
In 2005 Shepherd signed a three-year deal with new franchise, the Western Force.
Following a successful season with the Force in their inaugural season in 2006, Shepherd was included in the Wallabies squad. He scored his first Test try on June 24, during the 2006 mid-year Test series against Ireland.
On September 9 that year Shepherd received his first starting cap when he was selected on the wing for the Wallabies in the final Test of the 2006 Tri-Nations series - against South Africa.
He was a member of the Australian squad at the 2007 World Cup and was selected at fullback for the final pool game against Canada in Bordeaux.
In May this year it was announced that Shepherd had signed with the Saints.
However, this deal has now been cancelled.