Stuart McCloskey has been ruled out Ireland's final November international against South Africa on Saturday after suffering a recurrence of a groin injury.
The Ulster centre was withdrawn after just 27 minutes of the team's 46-19 victory over Australia last Saturday and replaced by Bundee Aki.
McCloskey suffered the same injury in Ireland's game against New Zealand on 1 November and missed the win over Japan.
Head coach Andy Farrell has not called anyone up as cover but has options in the form of Aki, Robbie Henshaw, Garry Ringrose, Ciarán Frawley and Tom Farrell.
Prop Thomas Clarkson passed his head injury assessments after being replaced against Australia late on and is expected to train fully this week.
Leinster players Josh van der Flier and Ringrose are back in contention to face the Springboks at Aviva Stadium (5.40pm).
The flanker and centre have recovered from hamstring issues after being ruled out of the 41-10 win over the Brave Blossoms.
Watch Ireland v South Africa in the Quilter Nations Series on Saturday from 4.30pm on RTÉ2 and the RTÉ Player. Follow a live blog on the RTÉ News App and on rte.ie/sport. Listen to live commentary on RTÉ Radio 1
