Sexton is uncertain to play after a leg injury suffered in the 32-19 win over France on February 11.
Carbery, who has 37 caps, was a surprise omission from the squad for Ireland’s opening two Six Nations matches, in which they also beat Wales in Cardiff.
A calf injury will keep winger Keith Earls out of the trip to Rome, while locks Tadhg Beirne and Joe McCarthy will miss the rest of the competition. Jamison Gibson-Park (hamstring), Robbie Henshaw (wrist) and Tadhg Furlong (calf) also remain unavailable.
Front-rowers Dan Sheehan and Cian Healy returned to the 37-man squad having overcome hamstring issues.
Rob Herring was also included, continuing his return to play protocols after suffering a head injury against France.