Ireland duo Brian O'Driscoll and Sean O'Brien are expected to be fit to face Scotland at Murrayfield on Sunday.
The Leinster pair picked up injuries during the 12-6 loss at home to England two weeks ago, but are now back in full training.
The news is a welcome boost for the Irish, who have been beset by injuries and will be missing a string of first-choice players this weekend.
Team manager Mick Kearney said on Tuesday: "Brian and Sean trained this morning and are expected to be fully involved for the rest of the week."
Uncapped Ulster centre Luke Marshall has recovered from the dead leg he suffered on provincial duty last Friday and will replace the injured Gordon D'Arcy but lock Donnacha Ryan remains a doubt for the weekend.
"Luke Marshall has recovered really well from his dead leg and trained fully this morning," said Kearney. "There are no concerns about him.
"Donnacha continues to recover from a back spasm. He took part in some of the session today and we're continuing to monitor his rehab."
Head coach Declan Kidney is planning to name his team to face Scotland at lunchtime on Wednesday.
D'Arcy and Simon Zebo will miss the rest of the Six Nations, Mike McCarthy appears to have suffered a similar fate because of a knee problem, and Jonathan Sexton will miss the Scotland game, and may not have recovered in time to face France a fortnight later.
Paul O'Connell, Stephen Ferris and Tommy Bowe have been missing throughout the Six Nations and prop Cian Healy has been suspended for three weeks for stamping on England's Dan Cole.
Kearney said: "My own view is that there was a certain degree of ambiguity in the hearing's decision.
"While Cian was suspended for three weeks, he was ruled out of rugby for four weeks. That's an area we'd like clarity on. But, unless we feel we have very good grounds for appeal, we won't appeal it."