Leinster scrum-half Eoin Reddan would be expected to fill the void should O'Leary fail to recover with Stringer, whose last Six Nations appearance was in March 2009, next in line.
But Ireland team manager Paul McNaughton was quick to point out Stringer's call-up was purely precautionary and that O'Leary's prospects of featuring against the defending champions are far from over.
"Tomas has had a stiff back which has not sufficiently improved over the course of the week, so we felt it was prudent to call Peter up to remain with the squad," he said.
"Tomas is not ruled out of the game, but we will wait and see how he progresses over the next 48 hours before making any decisions on changes to the match 22."
Stringer was due to take part in Munster's Magners League clash with Treviso this weekend, but he will now remain with the Ireland squad until Sunday.