Ireland centre Gordon D’Arcy was left behind in Dublin as a precaution when the squad travelled to New Zealand yesterday (Tuesday).
The 31-year-old Leinster player will join up with his teammates later this week after picking up a calf strain at a recovery session.
"On medical advice we are not going to bring Gordon out on this flight and delay it by about 48 hours," team manager Paul McNaughton said.
"Gordon is not ruled out of anything yet - it is a slight calf strain and we will re-scan it before he flies out."
Ireland kick off their World Cup campaign against the United States on Sunday, September 11.
