Isaac Boss, who skippered Leinster in last weekend's 10-10 draw away to Sale Sharks, partners Ian Madigan at half-back.
The 23-year-old Madigan, who was the province's Powerade Young Player of the Year last season, will make his 50th appearance after featuring 26 times last season.
Noel Reid continues his centre partnership with Brendan Macken, with Andrew Conway named in a fast-paced back-three alongside Fionn Carr and full-back Isa Nacewa.
Tom Denton could be set to make his competitive debut for the team if he appears off a replacements bench which includes six players who have come through the Leinster Academy.
LEINSTER (v Scarlets): Isa Nacewa; Andrew Conway, Brendan Macken, Noel Reid, Fionn Carr; Ian Madigan, Isaac Boss; Heinke van der Merwe, Richardt Strauss, Jamie Hagan, Damian Browne, Devin Toner, Dominic Ryan, Shane Jennings (capt), Leo Auva'a.
Replacements: Aaron Dundon, Jack McGrath, Martin Moore, Tom Denton, Jordi Murphy, John Cooney, Collie O'Shea, Darren Hudson.