Ireland forwards Dan Sheehan, Jack Conan and Dave Kilcoyne will not be involved in their side's World Cup opener against Romania on Saturday.
All three are finishing their rehabilitation from injuries, ruling them out of the Pool B encounter in Bordeaux.
"A few guys will not be involved at the weekend," confirmed Ireland assistant coach Paul O'Connell on Tuesday.
Hooker Sheehan and back row Conan have been suffering from foot injuries.
Munster prop Kilcoyne has been nursing a hamstring complaint.
Leinster forward Conan sustained his foot problem in the warm-up win over Italy on 5 August, with provincial team-mate Sheehan spraining a foot the following week in a victory over England.
"Dave Kilcoyne is struggling a bit but should be ok for next week," O'Connell told reporters at the Irish training base in Tours.
The former Ireland second row reported an otherwise clean bill of health ahead of the game against the world ranked number 19 side.
O'Connell, who played in four World Cups, said the Ireland squad would not "reinvent the wheel in terms of preparation" for their forthcoming pool matches against Romania, Tonga, South Africa and Scotland, but "wanted to evolve and get better for sure".
"We have real continuity in terms of how we play, in terms of selection, in terms of knowing each other, what each other are about and how we enjoy ourselves and switch off.
"We haven't prepared for this game [the opener against Romania] any differently to how we prepare for any other game.
"The only thing is we have more familiarity when we play the likes of Wales - it's a continuation of the story from the last time we played them - we're seeing what have they changed from the last time, the players know them really well, so they're bringing their own information.
"It's like the continuation of a story, the same with the other Tier One nations. It changes a little bit this week. There's a little bit of learning this week and the players have been really diligent in going about that.
"Hopefully that pays off on the field on Saturday."