The second row forward, who has won 10 Wales caps, takes the place of Paul Tito who moves to the bench for the match. The only other change in the forwards from the team that defeated Edinburgh last Saturday sees Sam Warburton start at Openside in place of the suspended Martyn Williams.
The only change in the back sees Ceri Sweeney start at outsidehalf in place of the injured Dan Parks.
Cardiff Blues Team:
15 Ben Blair 14 Leigh Halfpenny 13 Casey Laulala 12 Tom Shanklin 11 Chris Czekaj 10 Ceri Sweeney 9 Richie Rees
8 Xavier Rush 7 Sam Warburton 6 Maama Molitika 5 Deiniol Jones 4 Bradley Davies 3 Taufa'ao Filise 2 T Rhys Thomas 1 Gethin Jenkins
16 Rhys Williams 17 John Yapp 18 Scott Andrews 19 Paul Tito 20 Andries Preotrius 21 Lloyd Williams 22 Dafydd Hewitt 23 Tom James
Castres Olympique Team
15 Romain Teulet, 14 Vincent Inigo, 13 Yoan Audrin, 12 Seremaia Bai, 11 Marc Andreu, 10 Cameron McIntyre, 9 Sebastien Tillous-Borde,
1 Yannick Forestier, 2 Ben Kayser, 3 Luc Ducalcon, 4 Joe Tekori, 5 Matthias Rolland, 6 Ibrahim Diarra, 6 Yannick Caballero, 8 Chris Masoe [capt].
M Bonello, A Giorgadze, D Saayman, S Murray, S Malonga, T Sanchou, P Bernard, P Garci