O'Gara has to settle for a place on the bench for the clash with the World Champions after Kidney chose to hand the No10 jersey to Leinster youngster Jonathan Sexton instead.
But Kidney has explained that his high-profile selection choice had more to do with learning about the international future of Sexton rather than bringing an end to the top-level career of his veteran playmaker.
"I know we have a world-class outside-half in Ronan but we have to find out things about ourselves," said Kidney.
"Jonathan had a good game last week but, with respect, Fiji were short of a few so it was difficult to read. I need to find out more."
And while Kidney is clearly excited about the prospect of the 24-year-old Sexton transferring his fine Magners League form on to the world stage, Ireland's Grand Slam winning boss is by no means closing the door on O'Gara.
He admits that the Munsterman is naturally frustrated not to be involved against the Springboks but he has been pleased to see O'Gara continue to train with just as much enthusiasm in the lead up to the final match of the autumn series.
"I know we still have Ronan available," added Kidney.
"He's disappointed he's not playing but I can't pick everybody all of the time.
"Ronan is disappointed but is the perfect pro. He's taken it on the chin, has continued training and has contributed to the team exactly as he would normally."
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