Toe surgery to rule Munster's Ryan out for up to six months
Ireland lock Donnacha Ryan (inset) will have to undergo surgery on his troublesome toe that will sideline him for four to six months.
"Donnacha has done everything that has been asked of him and we know it has been a tough time for him with the option of surgery available as a last resort. We are now at that point," said coach Anthony Foley.
An extensive, carefully managed rehabilitation process has not worked out, leaving Ryan to contemplate further time out, putting in jeopardy his attempts to recover his jersey for the Six Nations.
It also seriously undermines his aim to play a role in Munster's European campaign.
Meanwhile, Leinster's Shane Jennings will be out of the game for three to four weeks with a hamstring strain.
Ireland coach Joe Schmidt will be reassured that Dave Kearney returned to on-field activities for the first time on Monday as the next step in his rehabilitation programme from a knee injury.
Hooker Richardt Strauss is much closer to a return to first team action. He was able to engage in his first contact session on Monday as he makes his way back from a severe hamstring tear last season.
Unbeaten Connacht should have wing Danie Poolman back from illness when The Westerners travel to in-form Glasgow on Friday.
Another wing Tiernan O'Halloran will undergo surgery on a troublesome knee and is expected to be sidelined for a further 3-4 weeks, while flanker Willie Faloon and wing Niyi Adeolokun are fit to play.