Sexton has started Ireland's three recent matches against Scotland, Wales and England in the midst of a heavy workload for his Parisian club, following on from a hectic Lions tour in which he began all three Test matches, scoring a crucial try in the third in Sydney.
But Schimdt is confident that Sexton's injury is not as bad as first feared.
"It wasn't bad, he's fully functioning and can still pass and do everything," said Schmidt.
"But we're going to get some more feedback over the next few days. Hopefully, he'll be fine.
"He's gone back to Paris and we've got some scans to be read as well and we'll get some feedback on that by Thursday when we're next out.
"I predict that he should still be available for the final two games."