Jordan Larmour will miss Ireland's remaining Six Nations matches and the Autumn Nations Cup campaign after suffering a dislocated shoulder, his province said Monday.
Full-back Larmour missed Leinster's PRO14 win at Benetton on Saturday and the 23-year-old is now set to undergo surgery.
That will mean he is ruled out of Ireland's rescheduled Six Nations games against Italy on October 24 and France the following week, as well as the new Autumn Nations Cup that starts in November, with the Irish up against Wales, England and Georgia.
A Leinster statement said: "Jordan Larmour was withdrawn against Benetton Rugby with a dislocated shoulder and will have a procedure this week.
"There is no timeline on his return yet until after the procedure but he will be unavailable for the upcoming Guinness Six Nations and Autumn Nations Cup."
Ireland are currently fourth in the Six Nations table but only just four points behind joint-leaders England and France and with a game in hand over the top two.
Ireland captain Johnny Sexton (hamstring) and Leinster team-mates Ronan Kelleher (quad) and Andrew Porter (hamstring) are due to join up with the national squad as planned before undergoing assessment on their respective injuries.