The Ospreys have said that Tommy Bowe, who has already been ruled out of Ireland's RBS Six Nations opener against Italy on Saturday week, could also miss the match against France the following weekend.
A knee injury called time of Bowe's trip to Rome, with no date as yet set for his return. However Ospreys' head physio Chris Towers has now revealed that the winger is unlikely to face the defending Six Nations champions at the Aviva Stadium on February 13.
"We're continuing to liaise with the Irish medical team regarding Tommy's condition and the management of his injury," said Towers.
"We've taken the decision to continue to offload him, allowing the knee to settle further, and at this stage remain optimistic that the problem will resolve in the short term.
"We are hopeful that in a couple of weeks, if he continues to improve as he is, he will be able to get back into some rugby specific training without any reaction or ill effect.
"The signs are encouraging at this stage, but it is clear that it will be another couple of weeks before we can confirm whether or not this problem will impact on more than just the first couple of Six Nations fixtures."
Ireland's preparations for the Six Nations have been hit by an injury crisis that has robbed them of eight players capable of featuring in the matchday 22.
Head coach Declan Kidney can ill-afford to lose such an effective player as Bowe for the first two games of the championship, especially with three of his potential replacements - Shane Horgan, Geordan Murphy and Andrew Trimble - also injured.