The 30-year-old is captain Brian O’Driscoll’s long-term partner in the Ireland midfield and has started every match in both the 2010 and 2011 RBS 6 Nations.

The injury occurred in Leinster’s Heineken Cup final defeat of Leicester and would be a big blow to Kidney’s preparations.

“Unfortunately Gordon's ankle didn't solve itself so he needed an operation and it will take a good six weeks to be running fully, then you need a pre-season, which is another couple of weeks, so it's getting tight,” Kidney said.

Ireland’s World Cup preparations kick off against Scotland on Saturday and while momentum heading to New Zealand is important, Kidney says it is secondary to making sure his final 30-man squad are all fit and raring to go.

He said: “We know we need to be match-fit. If you play four teams are you increasing the odds? I don't think so really.

“I don't think I'll be playing anyone in all four games. I mightn't be playing too many in three games.

“The object really is to win the matches, to perform as well as we can and to get 30 fellas match-fit -- at least 30 fellas match-fit, because when you go down there, you don't know who you're going to need at any given time.

“If you go down with 15 of them fit by playing two games and then you have to call on someone and they're not match-fit, you're going to say: ‘Do I go for the unmatch-fit fella or the semi-fit fella? So five games is about getting fellas match-fit.”