O'Driscoll was forced from the field with 12 minutes remaining at the Aviva Stadium and was sent for an x-ray in Dublin to determine the severity of the injury.
Leinster and O'Driscoll must now wait for the results of the examination to discover whether the 107-timed-capped centre requires surgery.
"He's going for an X-ray and could have a crack in the jaw, the treatment for which we're not sure yet," said Ireland coach Declan Kidney.
"If it's just a crack, he might be able to avoid surgery and having a plate inserted. We'll just have to wait and see what the story is there.
"He felt okay; it just felt prudent to get him off when we did. Brian felt comfortable himself, he asked for a few minutes but the medics said he had to come off."
Leinster currently sit at the helm of Pool 2 after victories over Heineken Cup new boys Racing-Metro 92 and Saracens.