Magners League leaders Munster will be without star scrum-half Tomas O’Leary for up to two months.
The Ireland No9 suffered a thumb injury in Saturday’s defeat to rivals Leinster at the new Aviva Stadium.
O’Leary has now had surgery on the injury and will be unavailable for selection for between six and eight weeks.
The 26-year-old will miss Saturday’s Heineken Cup opener at London Irish and the Round 2 clash with Toulon, as well as up to three Magners League ties.
He is now a serious doubt for the start of the international calendar too, with only the last of Ireland’s autumn Tests falling more than eight weeks away from today.
The news is a further blow for the 2009 Magners League Champions after they saw centre Lifeimi Mafi handed a seven-week suspension that rules him out of action until November 22.
But the Red Army have strength in depth at scrum-half and can call on veteran Ireland international Peter Stringer and 24-year-old Duncan Williams to fill the void.