Fergus McFadden has been ruled out of action until the New Year as a result of a high grade hamstring injury.
The Leinster back picked up the injury in training last week and now faces four months on the sidelines as he rehabilitates the muscle injury.
The Donnybrook-based club confirmed that the Ireland winger "had a procedure over the weekend and will be out of action for four months".
Back coach Felipe Contepomi said: "He's been to a specialist in England and unfortunately he has an injury that will keep him out for some months.
McFadden picked up an injury at the end of last season but returned to action at the beginning of the 2018-19 season, coming on as a replacement against Cardiff Blues in August.
The Old Belvedere man has enjoyed three subsequent starts for the side, his last match in the 30-22 victory over Munster earlier this month.
Leinster confirm @fergmcfadden out for 4 months due to 'high grade' hamstring injury. @IrishRugby medics to assess Rob Kearney shoulder injury #rterugby pic.twitter.com/nAD4u9Wxg9
— Michael Glennon (@MicilGlennon) October 30, 2018
Dave Kearney, meanwhile, is set to return to full training following an adductor strain, while brother Rob, who did not travel with Ireland to Chicago for Saturday's clash with Italy, is still recovering from a shoulder injury picked up against Benetton last weekend and will be assessed by the Irish medical staff.
Will Connors (ACL) and Barry Daly (knee) remain out of contention due to their respective long-term injuries.
