In Sexton’s absence, James Ryan becomes Ireland’s 107th captain, while former England U20 fly-half Billy Burns – who made his debut against Wales on Friday – is named on the bench. He is going through concussion protocols this week.
Jamison Gibson-Park keeps his place at scrum-half ahead of Conor Murray, meaning Ireland’s half-backs are both inexperienced.
There are two further changes to the side. CJ Stander comes in for Josh van der Flier on the flank, while Keith Earls replaces Andrew Conway on the wing. Jacob Stockdale and Iain Henderson are also fit enough to return on the bench.
Ireland got their campaign off to a winning start with a 32-9 win over the Welsh at the Aviva Stadium in Dublin in the first ever game of the new competition.