Leinster will be without utility back Fergus McFadden for their crucial Champions Cup double-header with Harlequins after he suffered a thumb injury in last weekend's PRO12 win over the Ospreys.
McFadden has already undergone surgery to repair ligament damage to his thumb and is now set to miss all his province's Christmas schedule.
Leinster coach Matt O’Connor said: "Unfortunately Fergus McFadden picked up a thumb injury and had some surgery to repair ligaments and will be out for between four and six weeks.
"Fergus had the surgery on his thumb on Tuesday. Post training he was a little bit sore and we scanned it. I'm disappointed for him.
"He played quite well the other night and would have been in the panel. He’s incredibly frustrated with the injury run he’s had over the last little while. But he’ll be back."
McFadden is now in a race against time to be fit for the start of Ireland's RBS Six Nations campaign which gets under way against Wales at the start of February.
