O'Driscoll suffered the setback in Leinster's win over Ulster last weekend and could now be forced to sit out the Millennium Stadium encounter with Northampton.
The veteran centre's chances of appearing in Cardiff are only rated at touch and go by Leinster assistant coach Jono Gibbes despite a Leinster statement reading that 'Isaac Boss (tight hamstring), Brian O'Driscoll (knee) and Richardt Strauss (bruised hip) should all be back training by Wednesday and be available for selection this weekend'.
"Drico's probably the one that it's going to be a bit more wait and see," said Gibbes.
"We're positive with everyone else and, as the week progresses, I think they'll all get a hell of a lot better.
"Drico's going to take the most time and is the most concerning of the lot."
O'Driscoll's potential absence would be a major blow for Leinster, who have beaten French Champions Clermont Auvergne, English Champions Leicester and Heineken Cup holders Toulouse on their way to their second European final.
The 31-year-old Ireland captain has featured in 74 Heineken Cup fixtures since the 1999/2000 season and was a try scorer in the nail-biting semi-final win over Toulouse late last month.