Ireland could have four Lions back for Saturday's clash with France in Dublin, with flanker Sean O'Brien close to contention after a hamstring injury in the warm-up in Rome last weekend ruled him out of a first Test appearance in more than a year.
Jonathan Sexton, Jamie Heaslip, Rory Best, Cian Healy and O'Brien could all come into an Ireland side which was less than convincing in claiming an opening 26-3 win over Italy.
O'Brien was a late withdrawal from the starting XV, but a MRI scan on Sunday night confirmed the tearaway forward suffered only a minor hamstring strain in the warm-up in Rome and he is poised to train on Tuesday, Ireland team manager Mick Kearney said on Monday.
Sexton could displace Ian Keatley at fly-half at the Aviva Stadium after recovering from a head knock and number eight Heaslip could play following a shoulder injury.
Prop Cian Healy is available following a torn hamstring which required surgery last September, while a fifth Lion could also be fit after going off in Rome.
Hooker Rory Best is following return to play protocols following concussion.
Scrum-half Eoin Reddan (knee) and wing Dave Kearney (shoulder) are fit for selection.
O'Brien has not played for Ireland since the agonising late defeat to world champions New Zealand in November 2013 after two shoulder reconstruction surgeries.
Michael Kearney said: "Sean O'Brien did an MRI scan last night (Sunday) which confirmed a hamstring strain on the minor end of the scale.
"He is feeling good and we are hopeful that he will train with the squad tomorrow.
"If he comes through that, he will be available for selection. Whether that will happen or not, we will have to wait and see.
"Johnny Sexton is cleared to train fully and he is available for selection.
"Cian Healy trained fully last week, including some scrummaging which he came through very well and he is available for selection."