Dave Kearney and Eoin Reddan are expected to miss the start of Ireland's Six Nations defence after suffering injuries in Leinster's 20-20 draw with Wasps on Saturday.
The duo were high-profile casualties as the Dublin-based side progressed to the quarter-finals of the European Champions Cup.
Winger Kearney suffered a "significant" shoulder injury and scrum-half Reddan limped off with knee ligament damage, Leinster coach Matt O'Connor confirmed.
"Dave has got a bang on his shoulder. It's significant and he could be out for several weeks," O'Connor told reporters. "Eoin Reddan has a medial strain on his knee."
Ireland, the defending champions, kick off the defence of their title with a trip to Italy on February 7.
