The former British & Irish Lions skipper injured his shoulder in the warm-up matches and missed the defeat to England at the Aviva Stadium. But rest and physio seem to have done the trick to allow him to prepare for a fourth World Cup campaign.
"The shoulder feels okay. The more rest time I get, the better, but I've been training away and at the moment I don't see any reason why I won't be playing against the USA," said O'Driscoll.
The Irish camp has been boosted by the departure from Dublin of the Leinster duo of Gordon D'Arcy and Cian Healy and coach Declan Kidney hopes to be able to select from a full strength squad for the clash with the American Eagles.
Having lost all three warm-up matches both captain and coach will be looking for a return to winning ways as they build towards the crunch Pool clash with the Wallabies.
"Australia are ranked second in the world and are going to be a very tough team to beat," admitted O'Driscoll.
"We learnt in 2007 that there are no pushover Test matches at the World Cup. We had it hard against a couple of lesser-known international nations in Namibia and Georgia and we certainly won't be taking anything for granted - we'll focus on our first game and take it from there."