Castres boss David Darricarrere has rung the changes to his starting XV for Friday's Heineken Cup clash with the Ospreys at Stade Pierre Antoine.
Amongst the backs there are two changes to the side that beat Bayonne last weekened with Marcel Garvey replacing Romain Martial on the right wing and Paul Bonnefond taking over at inside centre in place of Remi Lamerat.
Up front, Pedrie Wannenburg is the only survivor in the back row, shifting from the flank to number eight where he takes over from Antonie Claassen. This means that Piula Faasalele and Ibrahim Diarra will be the starting flankers for this encounter.
In the second row Christophe Samson replaces Rodrigo Capo Ortega and packs down alongside Richie Gray. There's also a new front row with hooker Marc-Antoine Rallier and props Karena Wihongi and Mihaita Lazar starting at the expense of Brice Mach, Anton Peikrishvili and Saimone Taumoepeau.
France international Yannick Forestier is also included amongst the replacements as well as Seremaia Bai, who was on duty for Fiji last weekend against the Barbarians.
Meanwhile, Ospreys coach Steve Tandy has made seven changes to his run-on side for this encounter, welcoming back several Wales internationals who were on duty against Australia last weekend.
The back-line has three changes to the side that lost at home to Glasgow last weekend. On the wing, Aisea Natoga takes over from Hanno Dirksen while Dan Biggar and Rhys Webb replace Sam Davies and Tito Tebaldi as the starting half-backs.
In the forwards, Ryan Jones and Justin Tipuric are at number eight and openside flank respectively at the expense of Morgan Allen and Sam Lewis, who are both included on the replacements bench.
Alun-Wyn Jones is back in the second-row and as captain which means there is no place in the matchday squad for Lloyd Peers while Ryan Bevington starts at loosehead ahead of Duncan Jones, who is also riding pine.
The match will be significant for Aisea Natoga, who makes his Heineken Cup debut and Tyler Ardron who starts his first match in the tournament.
Tandy expects a daunting task against Castres.
"Facing the French champions back to back is always going to be a tough ask, but it's an exciting challenge that we are looking forward to," he said.
"You do look at the seedings and wonder how the French champions can be the fourth seeds in the pool, but we can't dwell on things like that, we've got to just get on with the job.
"Obviously we've been hit by injuries again and preparation time has been hindered by the fourth international, but that's part of the challenge as a region. With players unavailable it provides opportunities for others and we've got boys who have put their hands up in recent weeks and who have earned the right to be involved.
"Castres are back up at the top end of the table so their quality is absolutely clear. After a disappointing opening two rounds we know that we've got to put in some excellent performances over the next two weekends and that's what we are targeting.
"We know there's going to be a great atmosphere there as is always the case in France but we've got to stand up and be counted.
"Although training time for the Wales boys has been limited there's a great attitude and spirit among the group and we need to show the utmost professionalism as a group."
Castres: 15 Brice Dulin, 14 Marcel Garvey, 13 Romain Cabannes (capt), 12 Paul Bonnefond, 11 Remi Grosso, 10 Daniel Kirkpatrick, 9 Rory Kockott, 8 Pedrie Wannenburg, 7 Piula Faasalele, 6 Ibrahim Diarra, 5 Richie Gray, 4 Christophe Samson, 3 Karena Wihongi, 2 Marc-Antoine Rallier, 1 Mihaita Lazar.
Replacements: 16 Michael Coetzee, 17 Yannick Forestier, 18 Anton Peikrishvili, 19 Rodrigo Capo Ortega, 20 Yannick Caballero, 21 Julien Tomas, 22 Seremaia Bai, 23 Geoffrey Palis.
Ospreys: 15 Richard Fussell, 14 Aisea Natoga, 13 Tom Isaacs, 12 Ben John, 11 Jeff Hassler, 10 Dan Biggar, 9 Rhys Webb, 8 Ryan Jones, 7 Justin Tipuric, 6 Tyler Ardron, 5 James King, 4 Alun Wyn Jones (capt), 3 Aaron Jarvis, 2 Scott Baldwin, 1 Ryan Bevington.
Replacements: 16 Richard Hibbard, 17 Duncan Jones, 18 Dan Suter, 19 Morgan Allen, 20 Sam Lewis, 21 Tom Habberfield, 22 Matthew Morgan, 23 Tom Grabham.
Date: Friday, December 6
Venue: Stade Pierre Antoine
Kick-off: 21:00 local (20:00 GMT)
Referee: Peter Fitzgibbon (Ireland)
Assistant referees: David Wilkinson (Ireland), Olly Hodges (Ireland)
TMO: Jude Quinn (Ireland)