The 21-year-old has only started three matches in Europe's elite club competition since making his debut in the Irish province's semi-final win over Toulouse last season, but has scored tries in two of them, against Northampton Saints and Benetton Rugby in Rounds 4 and 6 respectively.

Those displays did enough to convince Farrell - who has moved up from defence coach after the World Cup to replace Joe Schmidt - to hand Doris the No.8 jersey, where he will play alongside Leinster team-mate Josh van der Flier and Munster flanker CJ Stander in the back row.

The other uncapped player in the 23-man squad is fellow 21-year-old Ronan Kelleher, with the Leinster hooker expected to feature off the replacements' bench in Dublin on Saturday.

Like Doris, Kelleher has also started just three Heineken Champions Cup matches, helping his Irish province secure the No.1 seeding and a home quarter-final with a try against Benetton Rugby in Round 1.

The four-time winners will host Saracens in the Heineken Champions Cup quarter-finals at the Aviva Stadium on April 4 in a repeat of last season's final, when Saracens triumphed 20-10 at St James' Park.

Doris and Kelleher are two of eight Leinster players in the starting XV, including captain Johnny Sexton, while Ulster - who travel to Toulouse in the Heineken Champions Cup quarter-finals on April 5 - will be represented by wing Jacob Stockdale, hooker Rob Herring and lock Iain Henderson.

Leinster Rugby No.8 Caelan Doris will win his first Ireland cap this weekend, having been selected by new head coach Andy Farrell for their opening Six Nations Championship match against Scotland after several impressive Heineken Champions Cup performances.