Brian O'Driscoll has been passed fit to face Castres at Stade Pierre-Antoine tonight. The Ireland captain underwent a fitness test shortly before kick-off and lines out alongside Luke Fitzgerald in the Leinster midfield.

Felipe Contepomi had been on standby to come into the side but must settle for a place on the bench after his return from injury.

There was one late change to the Leinster side with CJ van der Linde ruled out with a calf injury. Cian Healy replacese the South African prop with Ronnie McCormack promoted to the replacements.

Victory for Leinster will see them tighten their grip on Pool Two, extending their current six-point advantage over 2007 European champions Wasps, who host Edinburgh on Sunday.

Leinster beat Castres 33-3 in Dublin last weekend, but the French side should provide a much sterner examination on this occasion.

Castres Olympique: T Bouquie; C Sika, S Kefu, L Mazars, P Christophers; A Lagardere, S Tillous-Borde; G Lensing, A Giorgadze, D Saayman; J Tekori, L Nallet (capt); L Tomiki, C Masoe, F Faure. Replacements: M Bonello, L Ducalcon, C Gaston, K Kulemin, K Senio, T Sanchou, M Bourret.

Leinster: G Dempsey; S Keogh, B O'Driscoll, L Fitzgerald, R Kearney; J Sexton, C Whitaker; S Wright, B Jackman, C Healy; D Toner, M O'Kelly; R Elsom, S Jennings, J Heaslip. Replacements: R McCormack, B Blaney, T Hogan, S O'Brien, C Keane, F Contepomi, I Nacewa.