Leinster and Ireland prop Cian Healy is facing a two-month layoff after undergoing surgery on his right ankle on Wednesday.
The 26-year-old withdrew from Leinster's starting XV shortly before kick-off of last weekend's 40-7 Heineken Cup win over Northampton.
The eight weeks required to recover means he is set to miss his country's opening Six Nations fixtures against Scotland and Wales but he could feature against England on February 22.
"Cian had ankle surgery on Wednesday so he's unavailable for about eight weeks. He's doing good but he won't play for a while," said Leinster coach Matt O'Connor.
Healy had surgery on his left ankle during the offseason to correct an injury sustained on the British and Irish Lions tour to Australia and has made just four appearances for Leinster this season.
Rising star Jack McGrath is now set to start in Healy's place for Leinster in this weekend's rematch against Northampton in Dublin.