12 Dec, 14:42
Prop Cian Healy is expected to miss the start of the 2014 RBS 6 Nations after undergoing surgery on his injured ankle on Wednesday.
The trio have been added to the extended panel which will be reduced to the matchday 22 on Thursday afternoon.
In all, there are 15 Ireland internationals in the squad which also includes Scotland's Nathan Hines who featured in Leinster's 16-15 victory over Munster last weekend.
In-form full-back Rob Kearney scored his sixth try of the season in all competitions in Limerick, touching down for the second successive game against an Irish province.
Friday's game will be played in front of an increased capacity crowd of almost 20,000 and will be a sellout.
Speaking ahead of the quarter-final tie, Leinster coach Michael Cheika said that the squad are expecting their biggest test yet against Clermont Auvergne.
"When you come into the last week before the match, what you're looking for is confirmation of the things you've seen (of them) on tape, which we got," he said.
"It was a good physical match (against Stade Francais) so we were able to confirm some bigger picture issues.
"They didn't win the game, but if you look at their performances over the entire season, they're a pack of power.
"They have some unbelievable threats that we're going to have to deal with, as well as a really strong defence and an excellent kicking game, and they're very complete.
"As far as their position in the French league is concerned, two of the teams ahead of them aren't playing in Europe so the teams that are having to fight on two fronts are managing quite well, of which Clermont Auvergne is probably top of the pack."
He added: "We'd be confident that all of them (Shane Horgan, Kevin McLaughlin and Brian O'Driscoll) will play.
"Brian did some training over the weekend as did Kevin, while Shane trained today (Monday) although he has been doing some off-field stuff.
"We're taking an extra precaution to get him right for this week, and he'd be pretty confident as well, so there should be no problem there.
"Shane's an experienced player, but it doesn't mean it's an automatic entry because the lads have been playing very well.
"Girvan (Dempsey) has been playing out of his skin while Kearney's playing well, so it's going to come down to selection.
"But the fact that he's available for us, all going well this week, will make a lot of difference to the make-up of the team."
LEINSTER Squad (v Clermont Auvergne) - Backs (11): Shaun Berne, Gordon D'Arcy, Girvan Dempsey, Shane Horgan, Rob Kearney, Fergus McFadden, Isa Nacewa, Paul O'Donohoe, Brian O'Driscoll, Eoin Reddan, Jonathan Sexton.
Forwards (14): Leo Cullen, John Fogarty, Cian Healy, Jamie Heaslip, Nathan Hines, Bernard Jackman, Shane Jennings, Stephen Keogh, Kevin McLaughlin, Malcolm O'Kelly, Mike Ross, Devin Toner, CJ van der Linde, Stan Wright.