The Ireland fly-half has not played since suffering a hamstring injury in the Six Nations defeat against England, with a tendon tear in his left foot further extending his spell on the sidelines.
But Leinster say Sexton has "stepped up his rehabilitation in recent days", and could be involved at Thomond Park.
The 27-year-old is among the favourites to wear the Lions' number 10 jersey in Australia this summer, and head coach Warren Gatland will welcome the news Sexton is closing on a return to fitness.
Brian O'Driscoll will make his return to action for the province in Limerick, with his ban for stamping during Ireland's defeat in Italy set to expire.
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