The Naas number 8 will start alongside Kevin McLaughlin and Sean O'Brien in a combative back row unit, with skipper Leo Cullen partnering Scotland international Nathan Hines in the second row.
Gordon D'Arcy partners Brian O'Driscoll in midfield, with Rob Kearney starting at full-back in an exciting back-three alongside Shane Horgan and Isa Nacewa. Eoin Reddan and Shaun Berne are the starting half-backs.
Stan Wright returns from injury for the first time in two months and takes his place on the bench alongside Ireland internationals Bernard Jackman, Mike Ross, Malcolm O'Kelly and Girvan Dempsey.
Over 1,000 Leinster supporters are expected to travel to Llanelli this weekend, continuing the outstanding support for the province both at home and on the road in recent years.
LEINSTER (v Scarlets): Rob Kearney; Shane Horgan, Brian O'Driscoll, Gordon D'Arcy, Isa Nacewa; Shaun Berne, Eoin Reddan; Cian Healy, John Fogarty, CJ van der Linde, Leo Cullen (capt), Nathan Hines, Kevin McLaughlin, Sean O'Brien, Jamie Heaslip.
Replacements: Bernard Jackman, Mike Ross, Stan Wright, Malcolm O'Kelly, Stephen Keogh, Paul O'Donohoe, Fergus McFadden, Girvan Dempsey.