Dan Leavy has had his season ended by a knee injury.
The flanker had only returned from a 19-month absence from a knee problem in late October.
Leinster say Leavy has undergone a procedure to repair cartilage in his knee.
Since his return, the 26-year old managed nine appearances. The Independent say that Leavy's latest surgery was an elective one with Leinster hopeful of a summer return.
Meanwhile, Leinster have also given an update on Caelan Doris who was forced to withdraw from the Ireland Six Nations squad a fortnight ago.
Head coach Leo Cullen said the number-8 "flagged some concussive symptoms while in camp with Ireland".
Doris is not in contention for Leinster's Guinness PRO14 game with the Dragons this Friday night.
One man in contention for the Rodney Parade game is Rory O'Loughlin, who has recovered from a shoulder injury and is training fully.
Tommy O'Brien's recovered from an ankle issue, and is also in the running to face the Welsh side on Friday.
Michael Bent and Scott Penny have both resumed training from respective neck injuries, but the Dragons game is likely to come too soon.
And there's also light at the end of the tunnel for Adam Byrne. The pacy winger has been out of action since the end of last season. But he'll increase his training load this week as he nears the end of his rehabilitation from a hamstring injury.
Jimmy O’Brien (hamstring), Conor O’Brien (knee), Max Deegan (knee), and Vakh Abdaladze (back) remain long-term absentees.