Scrum-half Peter Stringer has been called into the Ireland squad as cover for Tomas O'Leary ahead of Sunday's RBS 6 Nations game against Scotland at Murrayfield.
O'Leary is still feeling the effects of a back spasm that troubled him during the build-up to Ireland's match against France on February 13.
The 27-year-old came through the Aviva Stadium encounter - which ended in a 25-22 defeat for Declan Kidney's men - but the injury flared up after the match and he has been unable to fully shake off the problem.
Stringer will remain with the squad until the Ireland medical team are happy with the fitness of O'Leary, who has been given another 24 hours to see if the symptoms clear up.
Kidney on Monday added eight players to the 22 who were on duty for the defeat to Les Bleus.
Andrew Trimble returned from a broken hand to represent Ulster in their victory over Scarlets on Friday, while fellow back Tommy Bowe has recovered from a knee injury and lined up for Ospreys in their win against Treviso on Saturday.
The return of Bowe will be particularly welcomed, given he has emerged as a key player for the Irish over the last two seasons.
Kidney also drafted in Denis Hurley and Gavin Duffy to boost the backs division, and added to his forwards options by bringing in prop Tony Buckley, second rows Mick O'Driscoll and Donnacha Ryan, and back-rower Rhys Ruddock.