Munster v Castres
There are two changes to the Munster side that defeated Edinburgh in the PRO14 last time out as Joey Carbery (fly-half) and CJ Stander (number eight) are both included.
Mike Haley starts at full-back with free-scoring Andrew Conway and Keith Earls completing the back three.
Rory Scannell and Chris Farrell continue their centre partnership with Conor Murray and Carbery paired together in the red of Munster for the first time in the half-backs.
The tight five are unchanged with Dave Kilcoyne, Niall Scannell and John Ryan in the front-row with Tadhg Beirne and Billy Holland in the engine room.
Peter O’Mahony captains the side from the side of the scrum with Chris Cloete and the returning Stander completing the side.
Jeremy Loughman, Ciaran Parker and Fineen Wycherley are in line to make their Champions Cup debuts off the bench.
Castres, meanwhile, have made six changes to their run-on side for this fixture between Pool Two’s first and second-placed teams.
There are three alterations in the Top 14’s side’s backline with Armand Batlle replacing Martin Laveau on the right wing while Florian Vialelle and Taylor Paris come in for Robert Ebersohn and David Smith at inside centre and left wing respectively.
In the pack, Alex Tulou takes over from Camille Gerondeau at number eight and he is joined in the back-row by Kevin Gimeno, who starts on the openside flank. This means that Castres’ captain Mathieu Babillot moves over to the blindside flank where he is preferred to Baptiste Delaporte.
The final change is in the second-row where Thibault Lassalle takes over from Rodrigo Capo Ortega.
Munster: 15 Mike Haley, 14 Andrew Conway, 13 Chris Farrell, 12 Rory Scannell, 11 Keith Earls, 10 Joey Carbery, 9 Conor Murray, 8 CJ Stander, 7 Chris Cloete, 6 Peter O’Mahony (c), 5 Billy Holland, 4 Tadhg Beirne, 3 John Ryan, 2 Niall Scannell, 1 Dave Kilcoyne
Replacements: 16 Kevin O’Byrne, 17 Jeremy Loughman, 18 Ciaran Parker, 19 Fineen Wycherley, 20 Arno Botha, 21 Alby Mathewson, 22 JJ Hanrahan, 23 Sam Arnold
Castres: 15 Scott Spedding, 14 Armand Batlle, 13 Thomas Combezou, 12 Florian Vialelle, 11 Taylor Paris, 10 Benjamin Urdapilleta, 9 Ludovic Radosavljevic, 8 Alex Tulou, 7 Kevin Gimeno, 6 Mathieu Babillot (c), 5 Thibault Lassalle, 4 Loic Jacquet, 3 Daniel Kotze, 2 Jody Jenneker, 1 Antoine Tichit
Replacements: 16 Kevin Firmin, 17 Paea Fa’anunu, 18 Marc Clerc, 19 Christophe Samson, 20 Yannick Caballero, 21 Julien Caminati, 22 Martin Laveau, 23 Rory Kockott
Venue: Thomond Park
Kick-off: 13:00 GMT
Referee: JP Doyle (England)
Assistant referees: Tom Foley (England), Paul Dix (England)
Television match official: David Grashoff (England)
Experienced front-row Mako Vunipola returns from injury to start for Saracens against Cardiff Blues in this crucial Pool Three clash.
The England prop has been sidelined through injury since the European tie at Glasgow Warriors in October, a match which also saw his brother Billy and Nick Isiekwe pick up injuries.
The latter scored as he featured for the first time in eight weeks last time out against Wasps; he partners Will Skelton in the second-row.
Hooker Jamie George broke his nose in what is being dubbed “the Battle of Glasgow”. He will make his 50th European appearance on Sunday.
Elsewhere, Schalk Burger comes in on the openside flank and Owen Farrell is reinstated at fly-half with Alex Goode switching back to full-back.
Meanwhile, Gareth Anscombe returns to the Cardiff Blues side for this fixture.
Anscombe, who starred in the number 10 jersey for Wales during their autumn clean sweep, starts at fly-half as John Mulvihill makes four changes from last week’s narrow defeat to Ulster at Kingspan Stadium.
Jarrod Evans is selected at inside centre and forms a new look midfield combination with Harri Millard, who will make his first European appearance for the region.
Dillon Lewis and Kirby Myhill are reintroduced to the starting line-up, replacing Scott Andrews and Kristian Dacey in the front-row, with former Saracen Rhys Gill retained at the loosehead following an impressive performance in Belfast.
The final change sees George Earle partner Seb Davies at lock, as Josh Turnbull moves to the blindside and Samu Manoa starts at number eight.
Saracens: 15 Alex Goode, 14 Sean Maitland, 13 Alex Lozowski, 12 Brad Barritt (c), 11 Alex Lewington, 10 Owen Farrell, 9 Richard Wigglesworth, 8 Jackson Wray, 7 Schalk Burger, 6 Michael Rhodes, 5 Will Skelton, 4 Nick Isiekwe, 3 Vincent Koch, 2 Jamie George, 1 Mako Vunipola
Replacements: 16 Tom Woolstencroft, 17 Richard Barrington, 18 Christian Judge, 19 Dom Day, 20 Calum Clark, 21 Ben Earl, 22 Ben Spencer, 23 Nick Tompkins
Cardiff Blues: 15 Matthew Morgan, 14 Blaine Scully, 13 Harri Millard, 12 Jarrod Evans, 11 Jason Harries, 10 Gareth Anscombe, 9 Lloyd Williams (c), 8 Samu Manoa, 7 Olly Robinson, 6 Josh Turnbull, 5 Seb Davies, 4 George Earle, 3 Dillon Lewis, 2 Kirby Myhill, 1 Rhys Gill
Replacements: 16 Ethan Lewis, 17 Brad Thyer, 18 Scott Andrews, 19 Macauley Cook, 20 Nick Williams, 21 Lewis Jones, 22 Steven Shingler, 23 Garyn Smith
Venue: Allianz Park
Kick-off: 13:00 GMT
Referee: Romain Poite (France)
Assistant referees: Cyril Lafon (France), Stéphane Boyer (France)
Television match official: Denis Grenouillet (France)
Racing v Leicester Tigers
Racing 92 head coach Laurent Travers has made six changes, including a positional switch, for their Pool Four encounter with Leicester Tigers in Paris.
In the backline, Simon Zebo takes over from Louis Dupichot on the right wing while Virimi Vakatawa comes in at outside centre where he takes over from Olivier Klemenczak, who moves to inside centre and Finn Russell starts at fly-half in place of Ben Volavola, who has been named on the replacements bench.
In the forwards, Wenceslas Lauret starts on the blindside flank in place of Fabien Sanconnie, who wore the number six jersey in Racing’s Top 14 loss to La Rochelle last weekend.
Bernard Le Roux replaces Boris Palu at lock while Cedate Gomes Sa takes over from Ben Tameifuna at tighthead prop. Dimitri Szarzewski will captain the side.
Meanwhile, Australia international duo Matt Toomua and Tatafu Polota-Nau return to the Leicester Tigers starting line-up for this fixture.
The Wallabies pair both played off the replacements bench in the Premiership game at Bristol last week but start the Pool Four encounter at the Paris La Defense Arena.
Harry Wells and Mike Fitzgerald are added to the forward pack and Ben White starts at scrum-half.
Campese Ma’afu and Will Evans are included among the replacements and Guy Thompson returns after missing the last two games with the leg injury suffered at Gloucester.
Racing 92: 15 Brice Dulin, 14 Simon Zebo, 13 Virimi Vakatawa, 12 Olivier Klemenczak, 11 Juan Imhoff, 10 Finn Russell, 9 Teddy Iribaren, 8 Antonie Claassen, 7 Baptiste Chouzenoux, 6 Wenceslas Lauret, 5 Leone Nakarawa, 4 Bernard Le Roux, 3 Cedate Gomes Sa, 2 Dimitri Szarzewski (c), 1 Eddy Ben Arous
Replacements: 16 Ole Avei, 17 Guram Gogichashvili, 18 Ben Tameifuna, 19 Dominic Bird, 20 Boris Palu, 21 Antoine Gibert, 22 Louis Dupichot, 23 Ben Volavola
Leicester Tigers: 15 Jonah Holmes, 14 Adam Thompstone, 13 Manu Tuilagi, 12 Matt To’omua, 11 Jonny May, 10 George Ford (c), 9 Ben White, 8 Sione Kalafamoni, 7 Brendon O’Connor, 6 Michael Fitzgerald, 5 Harry Wells, 4 Will Spencer, 3 Dan Cole, 2 Tatafu Polota-Nau, 1 Ellis Genge
Replacements: 16 Jake Kerr, 17 Campese Ma’afu, 18 Gaston Cortes, 19 Mike Williams, 20 Will Evans, 21 Guy Thompson, 22 Ben Youngs, 23 Matt Smith
Venue: La Defense Arena, Paris
Kick-off: 16:15 local (15:15 GMT)
Referee: Nigel Owens (Wales)
Assistant referees: Sean Gallagher (Ireland), Jonny Erskine (Ireland)
Television match official: Simon McDowell (Ireland)