Under-pressure Ireland coach Declan Kidney named Tuesday a team to play France without a starting or reserve fly-half as he waited on the fitness of Paddy Jackson.
Jackson has a tight hamstring which an Ireland team statement said Tuesday was "being carefully monitored during training this morning" ahead of Saturday's match at Dublin's Lansdowne Road.
The 21-year-old Ulster stand-off made his Test debut in Ireland's previous match, an 11-8 loss to Scotland at Murrayfield last month where the visitors failed to secure victory despite dominating possession and territory.
Ireland's cause wasn't helped that day by Jackson, who isn't a regular goalkicker for his province, missing three out of his four shots at the posts.
Jackson was only playing in Edinburgh because first-choice outside-half Jonathan Sexton suffered a hamstring injury of his own in the preceding loss to England in Dublin.
Veteran No 10 Ronan O'Gara, Ireland's most-capped player, was left out of Ireland's provisional 32-man squad to play France on Sunday, sparking fresh doubts about the 36-year-old's Test career.
O'Gara, capped 128 times by Ireland, came off the bench against Scotland but did not provide the calming influence his side needed.
Now the in-form Ian Madigan could start against France, with Kidney saying Tuesday the choice this weekend was between the Leinster man and Jackson.
"Paddy's chances of pulling through are very good and he should be good to train on Thursday," Kidney said Tuesday.
"We'll make the choice between Paddy and Ian then. I was told just a moment ago that it will be better to give Jonathan Sexton another week to recover.
"Jonny ran at top speed this morning. It would be easy to put him in against France, but it's better that he builds up his strength for another week."
So far Kidney, whose contract expires at the end of the season, has made three changes to his side.
Fergus McFadden was chosen on the right wing after Craig Gilroy suffered a groin strain, while lock Mike McCarthy, fit again after suffering a knee injury against England, replaced Donncha O'Callaghan -- now demoted to the bench.
And Cian Healy returned at loosehead prop instead of Tom Court after serving a suspension for stamping on England front-row Dan Cole.
Bench prop Declan Fitzpatrick has also been ruled out with a calf strain but his replacement has yet to be announced.
Ireland have won just one of their last 13 Tests against France, in 2009 when Kidney oversaw a Six Nations Grand Slam.
But France, despite being pre-tournament favourites, have lost all their three matches so far this season and are facing the prospect of a first championship whitewash since 1957.
Rob Kearney; Fergus McFadden, Brian O'Driscoll, Luke Marshall, Keith Earls; A.N.Other (TBC); Conor Murray; Jamie Heaslip (capt), Sean O'Brien, Peter O'Mahony; Donnacha Ryan, Mike McCarthy; Mike Ross, Rory Best, Cian Healy
Replacements: Sean Cronin, David Kilcoyne, A.N.Other (TBC), Donncha O'Callaghan, Iain Henderson, Eoin Reddan, A.N.Other (TBC), Luke Fitzgerald
Note: A.N.Other (TBC) = unknown player, to be confirmed