Greg Feek has hinted Ireland are ready to risk Johnny Sexton for their "do-or-die" quarter-final with Argentina, even if the linchpin fly-half is not 100 per cent fit.
Scrum coach Feek conceded Ireland can ill afford to take on the Pumas without Sexton, if there is any realistic chance the Leinster playmaker can stay the course in Cardiff on Sunday.
Sexton spent Wednesday's Ireland session running, and will be given Friday's training to prove he is sufficiently past his groin strain to start against Argentina at the Millennium Stadium.
Ireland could therefore now name Sexton in their team on Friday lunchtime, to give the combative outside-half every chance of being ready for their pivotal World Cup showdown.
"Johnny did about three-and-a-half kilometres of running today, so that's a positive," said Feek.
"We're quietly confident and we'll see how he goes on Friday.
"When you start to accumulate a number of games in a row, in the Six Nations you usually get two matches and then a week off, while in November you get three but you can still mix it around.
"But here it's do-or-die type stuff, so there might be some allowances around a few things, especially with our medical staff and strength and conditioners, they've got a good feel on things as well."
Ireland must do without injured duo Paul O'Connell and Peter O'Mahony for the rest of their campaign, while bullish back-rower Sean O'Brien is banned for Sunday's Pumas clash.
Ireland are understood not to have any intention to appeal O'Brien's one-week sanction, for punching Pascal Pape in Sunday's 24-9 victory over France.
Feek insisted Ireland can cope with what has to be a major pack reshuffle for this weekend's last-eight battle.
Ulster powerhouse Iain Henderson could start at blindside flanker, with Donnacha Ryan partnering Devin Toner at lock.
Chris Henry is likely to start at openside flanker in O'Brien's stead, with Jordi Murphy and Rhys Ruddock to contest the back-row berth on the bench.
Feek described Keith Earls as "just a bit battered" as the Munster flyer continues to recover from a bruising clash with France and juggernaut centre Mathieu Bastareaud last weekend.
"We're going to see how he goes, we're looking after him a bit and it's not too bad but we'll see how he goes on Friday as well," said Feek of Earls.
"He's just a bit battered, that's all. It's not too bad.
"At this stage, you want to do the best to make sure everyone is fit and available."