Rob Kearney, Fergus McFadden, Stephen Keogh and Trevor Hogan have been added to the extended squad, which is expected to be reduced on Thursday afternoon.
Grand Slam winner Kearney is back in contention after recovering from a bout of the mumps, while Wallaby flanker Rocky Elsom is being rested for Friday's game after a busy few weeks in blue.
Close to 12,000 tickets have now been sold for the Magners League clash with the Scarlets.
Tickets are on sale here as well as from Ticketmaster outlets nationwide. Tickets are also on sale in the Leinster Rugby Store and Spar shop in Donnybrook.
LEINSTER Squad (v Scarlets): Backs (11) - Simon Keogh, Chris Whitaker, Jonathan Sexton, Luke Fitzgerald, Gordon D'Arcy, Fergus McFadden, Brian O'Driscoll, Shane Horgan, Isa Nacewa, Girvan Dempsey, Rob Kearney.
Forwards (13) - Cian Healy, Ronan McCormack, John Fogarty, Bernard Jackman, Stan Wright, Leo Cullen, Trevor Hogan, Malcolm O'Kelly, Devin Toner, Stephen Keogh, Shane Jennings, Sean O'Brien, Jamie Heaslip.