Adam Idah will be sidelined for 10 weeks with knee ligament damage suffered while on Ireland duty this week.
Idah, 19, started Ireland's 3-0 defeat to England in their Wembley friendly on Thursday of last week and also the Nations League loss to Wales last Sunday.
However the Cork-bork striker sat out the third and final game of Ireland's latest international window against Bulgaria after suffering the knee injury.
His club, Norwich City, have confirmed that he will be out for 10 weeks, which means Idah is unlikely to return to action before the start of February.
Ireland's World Cup qualifying campaign begins in March and Republic boss Stephen Kenny will want the young attacker playing regularly for the Canaries before then.
Speaking after the Wales game, Kenny said: “He isn’t the finished article, nor would we claim he is, but he is someone with real potential.
“One of the things we have done is given players an opportunity with the World Cup qualifiers in mind.
"Adam Idah, I know he’s not scoring, is showing he is a different type of striker than we have had recently".
