Brian O'Driscoll could be sidelined for six weeks after suffering a suspected broken jaw at the weekend.
The 107-timed-capped Leinster centre will miss the crucial Heineken Cup double-header against Clermont next month.
O'Driscoll was forced from the field with 12 minutes remaining of Ireland's 29-9 victory over Argentina at the Aviva Stadium on Sunday.
The Irish captain was unable to perform post-game media duties and departed immediately to have the injury x-rayed before a decision could be made regarding surgery.
Leinster confirmed that there will be an update delivered today following this medical assessment, with an absence of five or six weeks the more likely option, which compound the confirmed absences of Rob Kearney and Luke Fitzgerald from the back-to-back Clermont clashes.
Leinster slipped to sixth in the Magners League with defeat away to champions the Ospreys and they will be without O'Driscoll when they return to Wales to face second placed Scarlets on Friday.
Meanwhile, Irish team-mate Tommy Bowe insists Ireland can reflect on a punishing autumn with pride despite winning just two of their matches.
A record 29-9 victory over old foes Argentina at Aviva Stadium ensured the Irish end the year in fifth place in the world rankings.
But the 50 per cent return from four Tests, combined with some mixed performances, is disappointing for a team of such ambition and ability. Only nine games remain until the World Cup, leaving Declan Kidney and his coach
ing lieutenants little time to continue shaping the style and look of the team. Ireland are seeking to capitalise on their strengths by playing attacking rugby and Bowe insists they succeeded when conditions were favourable.
“We can hold our heads up,” said Bowe, who started all four games.
“To finish with our highest winning margin against Argentina in the last game of the year is a great positive for us going through to the Six Nations. Whenever we've had dry ball, we've shown that we're able to throw it about. That's the type of rugby that we want to play. We have plenty of players who are willing to play good rugby.
“When we get the chance, we're able to cut teams open and we'll be looking to do more of that.”
The fact Ireland's best display was also their heaviest defeat — a 38-18 loss to New Zealand — sums up their perplexing autumn.
Beyond trouble at the set-pieces, it is hard to explain exactly why they have struggled, though it is no coincidence the All Blacks match was contested in dry conditions suited to an open game.
Even when subjecting Argentina, feared rivals who have traditionally been horrid opposition, to a record defeat it felt as though something was missing.
Meanwhile, the Irish Rugby Football Union have announced a new tiered pricing structure for next year's Six Nations matches against France and England.
Lansdowne Road failed to sell out at any time during the autumn with the 46,302 attendance for New Zealand the best crowd by some margin. The IRFU were condemned for their pricing strategy and have responded by introducing five categories for 30,000 seats, ranging in cost from £12.67 (€15) to £105.66 (€125).