Former Leinster star Elsom spent much of last term on the sidelines with ankle, hamstring and shoulder problems and unsurprisingly failed to hit top form in Australia's Tri Nations-winning campaign or the World Cup.
Elsom was stripped of his country's captaincy prior to the global gathering in New Zealand and now faces a big battle to re-establish himself as the Wallabies No1 blindside as the countdown to the 2013 Lions tour gathers pace.
But Foley, who tasted series success against the Lions in 2001, has defended his new signing's below-par performances by claiming Elsom was still hampered by hamstring issues even when he was deemed fit enough to play for either the Brumbies or the Wallabies last season.
"Few knew how hampered he was by the hamstring injury," said Foley.
"He played the international season last year with the hamstring partially detached, and pushed through it.
"Not many people know that and he would not use it an excuse.
"He would have liked to put some better performances but despite all the criticism he copped, there aren't too many players out there who would have been able to do that."
Elsom remains sidelined with the hamstring injury that has plagued him for close to three years and he will miss the first four of five rounds of the Super 15 season next month as a result.
But Foley hopes to have the 28-year-old back in contention for selection by the end of March and he is confident Elsom will soon be back to his best.
"Rocky won't start in round one," added Foley.
"There are some really positive signs, though, and I'm confident after the first month Rock will be over this injury and he can put it behind him."