Centre Garry Ringrose is set to miss Ireland’s Nations Championship fixtures next month with a hamstring injury.
The Irish Rugby Football Union (IRFU) said on Tuesday it is “unlikely” the 31-year-old will be involved in the home matches against Argentina, Fiji and South Africa and he has remained with Leinster to continue his rehabilitation.
Ringrose, who has scored 15 tries in 76 caps, missed last weekend’s United Rugby Championship win over rivals Munster at Aviva Stadium.
Fly-half Sam Prendergast remains a doubt for next week’s opener with the Pumas in Dublin because of a wrist injury.
The 23-year-old is continuing his recovery with the Ireland squad after missing the Munster game, while Leinster winger Jimmy O’Brien, 29, is following return-to-play protocols after sustaining a concussion against Munster.
Ireland head coach Andy Farrell has decided against calling up any replacements despite uncertainty over Tadhg Furlong’s availability.
The Leinster prop, 33, will appear before a disciplinary committee after being cited for an alleged groin grab against Munster.
Ireland beat Australia and Japan before losing to New Zealand in the southern hemisphere leg of the Nations Championship in July.
After facing Argentina on 6 November, Farrell’s side host Fiji and back-to-back world champions South Africa on 14 and 21 November respectively, before a finals weekend fixture at Twickenham’s Allianz Stadium on 28 and 29 November.
Argentina head coach Felipe Contepomi is faced with his own injury troubles.
Experienced Lyon prop Thomas Gallo has withdrawn from the squad with a wrist injury he sustained against Bayonne last weekend, while utility back Santiago Carreras limped off during Bath’s Prem defeat by Gloucester on Friday.
“He’s got to go for a scan, I’d be amazed if that’s not really bad news, which is gutting for him,” Bath head of rugby Johann van Graan said when asked about Carreras.
