But Shepherd has now signed for Sale Sharks, meaning he won't be in Oz when the Lions come calling next summer.
"Cameron has got great pedigree," said Sale's new director of rugby Bryan Redpath.
"We're hoping to get him fully fit, so that he can seize the opportunity to make a big impact for this club."
Injury issues had derailed Shepherd's switch to the Saints earlier this month but Sale have no such worries over the 28-year-old's fitness.
Shepherd, who won nine caps for the Wallabies and played Super Rugby for the Waratahs and the Force, has already proven himself on trial in the North West and will now look to force his way into the Sale line up for the Aviva Premiership opener at Exeter on September 1.
"It's a pleasure to have Cameron on board," added Sale's chief executive Steve Diamond.
"He's an experienced back three player who adds to our strength in depth. We realised that he was available and decided to invite him to Sale Sharks to train with us."
Sale have also signed South African centre Corne Uys from Newcastle Falcons as they look to build on last season's sixth-place Premiership finish.