O'Connell and Horgan will be required to play for their clubs this weekend to prove their fitness while Keith Wood, Geordan Murphy and Rob Henderson were all ruled out through injury.
Coach Eddie O'Sullivan has named a 25 strong side but three of those will revert to the A squad after the weekend. The starting line up will be will be announced on Tuesday next, February 26th in the Glenview Hotel following an open training session in Greystones RFC.
Forwards: Shane Byrne (Leinster), Peter Clohessy (Munster), Simon Easterby
Backs: Girvan Dempsey (Leinster), Guy Easterby (Llanelli), Denis Hickie (Leinster), Shane Horgan (Leinster), Tyrone Howe (Ulster), David Humphreys (Ulster), John Kelly (Munster), Kevin Maggs (Bath), Mike Mullins (Munster), Brian O'Driscoll (Leinster), Ronan O'Gara (Munster), Peter Stringer (Munster).