Ireland coach Joe Schmidt admits captain Paul O'Connell may not play again at the World Cup but is hopeful Johnny Sexton will be available to face Argentina in the quarter-finals.
A 24-9 victory over France at the Millennium Stadium means Ireland go through top of Pool D, pitting Les Bleus against New Zealand in the last eight, but the Irish win came at a cost.
Sexton hobbled off after 25 minutes with a groin problem before O'Connell departed on a stretcher during half-time with a hamstring injury. Peter O'Mahony was also carried off in the second half.
O'Mahony was seen walking with crutches and wearing a knee brace after the match but Schmidt believes O'Connell is worst off.
"Paul is the one who worries me most," Schmidt said. "It doesn't look great with Paul. It's an upper hamstring. We'll wait until Monday for the scan and the inflammation to go down.
"Johnny looks like an abductor to me. That's not a learned eye of a medic so we are probably going to get Johnny scanned on Monday.
"Johnny was already talking about next week in the changing room but I'm not sure if that means he'll be playing or not.
"Pete didn't seem too bad so we're hopeful with Pete. I think it's a twist of the ankle or knee but he was walking pretty well in the changing room. Hopefully he'll be okay."
There could be a fourth absentee for Ireland too after Sean O'Brien escaped punishment for appearing to punch France's Pascal Pape within the first minute of the match.
Pape was banned for 10 weeks in February after causing Ireland's Jamie Heaslip to damage three vertebrae and if O'Brien's misdemeanour is confirmed, he is likely to face a retrospective ban.
"I truly hope not," Schmidt said. "He was being held at the time, he swung but I don't think he was looking directly at the player but it's not for me to determine.
"It's not a closed fist. I'd be hopeful but it's not a decision for me. Hopefully it's not something that impacts on us.
"Considering the dressing room at the moment, we can ill-afford to lose another player, particularly a player of Sean's experience and standing in the group."
Despite their injuries, Ireland overpowered France with a stirring performance in Cardiff as second-half tries from Rob Kearney and Conor Murray sealed an impressive win.
Replacement fly-half Ian Madigan also produced a composed display in Sexton's absence, kicking eight points off the tee.
"I'm incredibly proud of the performance," Schmidt said. "The challenge grew more complicated when we lost Johnny, Paul and Peter - that's 200 plus caps and it does make it a challenge.
"We had to fight for everything we got. We were maybe a bit wasteful in the first half, we created some good opportunities and didn't finish.
"To be ahead at half-time gave us confidence and I was delighted with how the players clawed their way forward in the second half.
"It was an attritional battle but a battle that showed a lot of character in the side."
France struggled to mount any sustained spells of pressure and Les Bleus will have to improve if they are to stand any chance against the All Blacks at the same venue next Saturday.
"They fully merited the victory and for us we must recuperate and analyse," France coach Philippe Saint-Andre said.
"We must now prepare for a massive match on Saturday. We were dominated in the rucks, we struggled for ball at the set-piece.
"It's very complicated in a game of this intensity. We didn't lose on purpose.
"We don't have a choice who we face in the quarter-finals. We know it's a tough game but we're not out of the competition."