Ireland head coach Andy Farrell has confirmed that wing Jacob Stockdale injured his hamstring in Saturday’s 52-17 win over Fiji.
Stockdale was forced off in the 49th minute after pulling up following a tackle.
The 28-year-old was making his first Ireland appearance in 15 months after an impressive run of form for Ulster.
The injury will be a worry for Ulster, who begin their European Champions Cup campaign away to Toulouse on 8 December.
“He pulled up sharply with his hamstring,” Farrell said on Stockdale, who was seen at full-time with a bag of ice on his right hamstring.
“We’ll have to see how that is, but he pulled up quite sharp, so I was gutted for him.”
Farrell also said that full-back Jamie Osborne sustained an abductor injury in the first half of the win at the Aviva Stadium.
“He couldn’t carry on so that doesn’t look right at the minute,” added Farrell.
Ireland take on Australia in their final autumn international at the Aviva Stadium on 30 November.