It was in fact almost eight years to the day, back in October 2004 when Munster played Harlequins at Thomond Park, the big news of the week was that O'Callaghan and Shaun Payne would be missing from the Munster line-up. O'Callaghan tore a calf muscle in training in the weeks leading up to that game and his place alongside Paul O'Connell went to Trevor Hogan.

He was back for their next Heineken Cup outing against Ospreys and has been an ever present since with 208 Munster caps to his credit.

He was repalced in the game against Leinster when his hamstring tightened and though he did some running earlier in the week and thought he'd be able to travel to France that hope faded as the week went on.

He is expected to be in contention for a return to action when Edinburgh visit next weekend.