Munster v Scarlets
Keith Earls returns to Munster's starting line-up having recovered from a knee injury sustained against Leinster at the beginning of last month. He replaces Will Chambers, while Denis Leamy comes in for Peter O'Mahoney and Donncha O'Callaghan gets the nod ahead of the Donnacha Ryan.
Stephen Jones returns for the Scarlets, meaning Rhys Priestland moves to full-back in place of Daniel Newton. In the pack, Rob McCusker, Lou Reed and Rhodri Jones all start.
Toulouse v Harlequins
Toulouse have named a much-changed side for Sunday's showdown with Harlequins. Scrum-half Jean-Marc Doussain comes into the starting line-up ahead of Luke Burgess, while Yann David replaces Florian Fritz at outside centre. In the pack, Shaun Sowerby comes off the bench to swap places with Louis Picamoles at number eight. Yannick Nyanga drops to the replacements so Jean Bouilhou gets a start at flanker and France lock Romain Millo-Chluski returns to the second row. Up front, Yohan Montes is rotated with Jean-Baptiste Poux. Former Harlequin Gary Botha also loses his starting place, William Servat getting the nod instead.
Harlequins have also made a handful of changes as they look to bounce back from their first defeat of the season. Mark Lambert takes inured Joe Marler's place in the front row while Will Skinner joins captain Chris Robshaw and Nick Easter in the back row. Joe Gray comes back into the starting line up with Chris Brooker dropping to the bench as part of the continued hooker rotation policy from the coaching staff. In the backs, Tom Casson returns from an ankle injury at inside centre alongside Matt Hopper, whilst Ugo Monye is ready to start again after returning from injury over the past two weeks.
Meanwhile, Castres have chosen not to play Romain Teulet or Chris Masoe in the away game - the duo are replaced by Florian Denos and Jannie Bornman at full-back and number eight respectively. Max Evans is not included in the squad while Rory Kockott, Seremaia Bai and France prop Luc Ducalcon make the replacements bench.