The Irish talisman picked up the injury as the men from the Emerald Isle triumphed 29-9 over Argentina on Sunday.
The Test Lion in 2001 and 2009 and tour captain in 2005 was replaced by fellow Lion Keith Earl with 12 minutes to go and was sent for an x-ray to determine the severity of the injury.
Ireland coach Declan Kidney revealed O'Driscoll could have played on but was substituted on the advice of the medical team. Kidney is now hoping the 107-times capped centre will not require 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 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."