Ireland head coach Andy Farrell says Cian Healy's leg injury "does not look too good" after the prop was taken off on a medical cart in his side's defeat by the Maori All Blacks.
Healy came on as a replacement for Jeremy Loughman, who temporarily went off in the first half for a Head Injury Assessment.
If neither is available for Saturday's opening Test against New Zealand it would leave Ireland with just one fit loose-head prop - Andrew Porter - in their touring squad.
The visitors also lost centre James Hume to injury during the 32-17 loss in Hamilton and Jimmy O'Brien was taken off after sustaining a knock.
"Cian Healy does not look too good... he was in a bit of pain coming off the field. [The injury] has settled down a bit so we will have to see with him," assessed Farrell.
"Jimmy came off with a strain. He's feeling pretty good in the changing rooms.
"Jeremy actually passed his HIA with an independent doctor. We brought him off as a precaution. James has a bit of a groin injury that needs assessment tomorrow."
While Porter has established himself as Ireland's clear first choice loose-head, the potential lack of cover is now a major concern for Ireland as they prepare for three Tests against a side they have never defeated in New Zealand.
Connacht's Finlay Bealham has featured at loose-head before in international rugby but is a recognised tight-head.
Ireland's tour got off to a disappointing start as their largely experimental side were comprehensively outclassed by the Maori.
Most senior players were rested ahead of the Test opener in Auckland, with the squad's more inexperienced players offered a chance to shine.
"We're disappointed," reflected Farrell.
"We know it was a big week for the Maori boys but it was a big week for some of our guys, playing for Ireland for the first time.
"There was really good stuff from certain individuals but a lot of dumb stuff along the way.
"It was brilliant as far as our learning is concerned because that's what you've got to iron out if you want to make it to the top."