James Ryan has been confirmed as having an adductor injury - but he has not yet been ruled out of Ireland's summer series opener.
In the absence of Johnny Sexton, Ryan was due to captain his country against Japan at the Aviva Stadium on Saturday, and against the USA the following weekend.
But the Leinster second row suffered the injury in training last week and that is believed to have gone against him being selected as Alun Wyn Jones' replacement for the Lions
He narrowly missed out on Warren Gatland's initial Lions squad selection last week.
Ryan, 24, “will be monitored across the week to determine his availability for the Japan game," read an Ireland statement yesterday.
Andy Farrell is due to name his matchday squad for the Japan game on Thursday afternoon and, if Ryan doesn't make it, he will have to decide on a new captain.
Versatile Ulster back Michael Lowry has been training with the Ireland squad and is remaining in camp this week, although he has not as yet been added to the official 37-man squad.
