Rob Kearney is emerging as a new injury doubt for Ireland's World Cup opener against Scotland.
The experienced full-back is thought to have picked up a calf complaint in training on Monday, and has handed head coach Joe Schmidt a new injury headache.
Ireland are already "very, very likely" to be without powerhouse centre Robbie Henshaw due to a hamstring problem for Sunday's Pool A opener in Yokohama, according to scrum coach Greg Feek.
But losing Kearney would force boss Schmidt into another backline rethink, with Andrew Conway and Jordan Larmour in the frame to start at 15.
The ever-reliable 33-year-old Kearney impressed in Ireland's 19-10 victory over Wales that closed their World Cup warm-up fixtures in Dublin on Saturday, 7 September.
The 92-cap full-back ties Ireland's backline together, and Schmidt will be keen not to lose such a calming presence ahead of their crucial pool encounter.
Leinster centre Henshaw picked up a hamstring problem in Ireland training on Sunday, and is expected to miss Sunday's Scotland clash.
But Ireland have retained the 26-year-old in their squad and still hold hope he can recover in time to feature in the tournament.