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.
O'Driscoll trained successfully with the squad on Wednesday but Fitzgerald only partially trained and a decision on his fitness will be made on Friday.
The pair feature in an experienced Leinster squad which includes Shane Horgan who, alongside O'Driscoll (this season's joint-top try scorer with four), is one try short of scoring 25 Heineken Cup tries.
Shane Jennings, Malcolm O'Kelly, Leo Cullen and Rocky Elsom are named amongst a strong forward contingent.
However, South African prop CJ Van Der Linde misses out due to a toe injury and hooker Bernard Jackman remains a doubt with a swollen knee.
In all, there are 12 Ireland internationals in the squad.
Meanwhile, in excess of 3,000 Leinster supporters from Ireland and across the UK and Europe are expected to make the trip to London for this weekend's match.
The Official Leinster Supporters Club (OLSC) guide can be downloaded on www.leinsterrugby.ie.
LEINSTER Squad (v Harlequins): Backs (12) - Chris Keane, Chris Whitaker, Felipe Contepomi, Jonathan Sexton, Luke Fitzgerald, Simon Keogh, Gordon D'Arcy, Brian O'Driscoll, Shane Horgan, Isa Nacewa, Girvan Dempsey, Rob Kearney.
Forwards (14) - Cian Healy, Ronan McCormack, Bernard Jackman, John Fogarty, Ollie Le Roux, Stan Wright, Leo Cullen, Trevor Hogan, Malcolm O'Kelly, Rocky Elsom, Cameron Jowitt, Shane Jennings, Sean O'Brien, Jamie Heaslip.