The 33-year-old was forced off midway through the reigning Heineken Cup champions’ 59-22 victory at the RDS in Dublin on Satuday.
Following scans and a specialist review by the Ireland medical team, it was determined the Ireland captain will be side-lined for eight to 12 weeks.
Meanwhile, Ulster hooker Rory Best has also dropped out of Declan Kidney’s squad due to a neck injury which he picked up against the Dragons in their RaboDirect Pro12 encounter on Friday.
Best is expected to take four to six weeks to recover from sprained ligaments in his neck before undergoing further assessment of the injury.
— Irish Rugby (@irfurugby) October 30, 2012
On Monday, Leinster head coach Joe Schmidt had expressed his optimism over the severity of O’Driscoll’s injury, with the New Zealander confident the Irish skipper would be fit for the November Test matches.
“He sprained his ankle. He was going to play on. In the end, we measured up the responsibilities that he has got coming up and we replaced him,” said Schmidt.
“We don’t think at this stage that it is too serious.”
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