Jeremy Staunton (knee) and Peter Clohessy (ankle) were not in action and Anthony Foley took a restricted part because of a finger injury.
It was also confirmed yesterday that Kevin Maggs will be out of action for up to 12 weeks. This rules him out of the remainder of the Six Nations series and he could also miss Ireland's tour to New Zealand in June.
Irish team manager Brian O'Brien said, "Kevin must be considered doubtful for the New Zealand tour but we will monitor his progress and leave a decision on that until later."
With Maggs now sidelined, O'Sullivan faces something of a crisis at inside centre given that Rob Henderson, Jonathan Bell and Jason Holland are also out of the equation.