Stephen Ferris is in danger of missing Ireland's autumn Test series.
The Ulster flanker has been ruled out of next Saturday's clash against South Africa in Dublin and the following week's appointment with Fiji at Thomond Park, Limerick.
Ferris, 27, suffered an ankle injury during Ulster's RaboDirect PRO12 victory over Edinburgh three days ago.
The Irish Rugby Football Union said no decision has yet been made on his availability for Ireland's autumn finale against Argentina on 25 November.
Ferris' absence is the latest major injury blow for head coach Declan Kidney as Ireland prepare for their return to action after last summer's 3-0 Test series defeat in New Zealand.
Centre Brian O'Driscoll and hooker Rory Best have already been ruled out of the autumn games because of injuries, while lock Paul O'Connell has only taken a limited part in training.
Meanwhile, Ospreys back-rower Ryan Jones has been ruled out of Wales' autumn Test against Argentina with a shoulder injury, the Welsh Rugby Union have confirmed.
Wales assistant coach Robin McBryde said: "We took the decision out in Poland, we were aware Ryan had a niggle with his shoulder coming out to Poland so we thought it would be wise to get in there early and investigate if it was anything serious.
"Happily enough that isn't the case, but it is a case of doing quite a bit of rehab work for the remainder of this week in order for him to be fit for next week's match against Samoa, which is positive news."