Leinster's Heineken Cup hopes have been dealt a major blow after Brian O'Driscoll was ruled out for up to 12 weeks.
The three-time Heineken Cup winner suffered an ankle injury in the first half of Leinster's emphatic league victory over Cardiff Blues.
Head coach Joe Schmidt was initially optimistic over the stalwart centre but it has now been discovered that he suffered ligament damage and requires surgery.
O'Driscoll is set to be sidelined until mid-January and will definitely miss Leinster's crucial Pool Five double-header with Clermont Auvergne.
"O'Driscoll picked up an ankle injury in the game against the Cardiff Blues and following further scans and specialist review by the Ireland medical team, it has been decided that the injury will require surgery to repair ligament damage, ruling out
O'Driscoll from playing for 8-12 weeks," read a statement released by the Irish Rugby Union.
Leinster, targeting their fourth Heineken Cup title and fourth in a row, sit second and two points adrift of the French giants.
But the back-to-back clashes are likely to be decisive in decided who advances from the Pool stages.
