Gloucester, Worcester, Montpellier and Cardiff Blues have named their sides for Thursday's Challenge Cup matches.
Gloucester v Worcester
Tom Savage will make his 100th competitive appearance for Gloucester as the Cherry and Whites.
The 26-year-old will reach his century in his fifth season with Gloucester as one of ten changes to the starting line from the side that defeated the same side at Sixways last week.
Into the starting line-up come Rob Cook, Charlie Sharples, Billy Twelvetrees, Jonny May and James Hook in the backs.
Up front, there is a new look front row in Yann Thomas, Darren Dawidiuk and Nicky Thomas who will make his first start for the club. In the second row, Savage will partner Mariano Galarza, who lines up against his former club again, as does the final new face, Matt Kvesic.
Gloucester currently lead the pool by eight points, so victory at Kingsholm, which would be a competition record 13th in succession, would go a long way towards clinching a quarter-final berth.
Previewing the game with the media this week, Jonny Bell acknowledged that playing the same opponent for the second time in seven days presents a unique challenge, but that Gloucester are ready for the task in hand.
"These back to back games are a challenge in that you know each other inside out. They'll be looking at things from last week, areas they can attack, and we will also be looking at opportunities that we want to expose," he said.
"But it's about getting our mindset right. We want to do well in this competition, so we aim to turn up in the right frame of mind, as we do for every game, as we want to deliver.
"This competition has special meaning for us and we want to progress. We're in the box seat at the moment and things are in our destiny. A top two seeding for the quarter-final is important because there are some great teams in the tournament and securing a quarter-final at Kingsholm, in front of a passionate home support, is ultimately what we want to do.
"So, we need to make sure that we control things well on Thursday and deliver, because Worcester are coming to Kingsholm to try and upset the apple cart.”
Meanwhile, the Warriors, who are offering long odds with Betbright, have made five changes to the forward pack.
An all-change front row sees Val Rapava Ruskin, Ben Sowrey and Mike Daniels promoted from the subs bench while Fijian lock Tevita Cavubati comes into the starting line-up next to Dan Sanderson.
Sam Betty will start in the back row alongside Carl Kirwan and Marco Mama as Warriors go in search of a second win in Pool 4 against their local rivals.
The backline remains unchanged with Charlie Mulchrone captaining the side from scrum-half alongside stand-off Ryan Lamb.
Centre Andy Symons looks to find some form after a lengthy injury lay-off next to Alex Grove, who is set for his 150th appearance for the club.
Ben Howard, Tom Biggs and Dean Hammond occupy the back three while Huw Taylor and Tiff Eden could make their first Warriors appearances of the season from the replacements bench.
Head Coach Carl Hogg said: "It's a European game so it's got its own rights and playing against Gloucester is always a special fixture.
"It does give us an opportunity to see how some of our younger players are progressing and asks questions of whether they're capable of playing in the Premiership.
"Playing back-to-back allows us to see what we've learned from last Thursday night and to see if we can apply those lessons into this week's game.
"The endeavour, energy and intensity this group have shown in the competition has been great.
"It's just whether we can be more accurate in our decision making and processes which will be key to the outcome this Thursday night."
Gloucester: 15 Rob Cook, 14 Charlie Sharples, 13 Henry Purdy, 12 Billy Twelvetrees (c), 11 Jonny May, 10 James Hook, 9 Greig Laidlaw, 8 Lewis Ludlow, 7 Matt Kvesic, 6 Jacob Rowan, 5 Mariano Galarza, 4 Tom Savage, 3 Nicky Thomas, 2 Darren Dawidiuk, 1 Yann Thomas
Replacements: 16 Tom Lindsay, 17 Dan Murphy, 18 Josh McNulty, 19 Elliott Stooke, 20 Tom Hicks, 21 Willi Heinz, 22 Billy Burns, 23 Mark Atkinson
Worcester: 15 Ben Howard, 14 Dean Hammond , 13 Alex Grove, 12 Andy Symons, 11 Tom Biggs, 10 Ryan Lamb, 9 Charlie Mulchrone (c), 8 Marco Mama, 7 Carl Kirwan, 6 Sam Betty, 5 Tevita Cavubati, 4 Dan Sanderson, 3 Mike Daniels, 2 Ben Sowrey, 1 Val Rapava Ruskin
Replacements: 16 Jaba Bregvadze, 17 Ryan Bower, 18 Gareth Milasinovich, 19 Darren Barry, 20 Huw Taylor, 21 Jonny Arr, 22 Tiff Eden, 23 Max Stelling
Date: Thursday, December 17
Kick-off: 19:45 GMT
Referee: Ian Davies (Wales)
Assistant Referees: Simon Rees (Wales), Martyn Lewis (Wales)
TMO: Gareth Simmonds (Wales)
Montpellier v Cardiff Blues
Jannie du Plessis will make his debut for Montpellier as they host Cardiff Blues.
Du Plessis is one of ten changes made by Jake White after last week's defeat away in the Welsh capital.
Demetri Catrakilis and Nic White return at half-back, while Fulgence Ouedraogo replaces Wiaan Liebenberg in the Montpellier back row.
Robins Tchale Watchou comes in at lock while Timoci Nagusa shifts from the right wing to outside centre.
Meanwhile, young centre Garyn Smith will make his European debut for Cardiff Blues.
Wales U20 ace Smith, who has made 14 appearances for Cardiff Blues but never in European action, is called into the starting line-up for the Challenge Cup encounter as head coach Danny Wilson makes five changes to the side that defeated the French side last week.
Scrum-half Tavis Knoyle is the other change in the back division where he will combine forces with fly-half Jarrod Evans.
Prop Gethin Jenkins returns to captain the team in the front row while lock Lou Reed is called up to the second row to partner Jarrad Hoeata.
The final change is a recall for fit-again Italian international number eight Manoa Vosawai, who slots in the back row alongside Josh Navidi and Macauley Cook.
USA international Blaine Scully is named among the replacements alongside utility back Tom Isaacs and talented young prop Dillon Lewis.
Head Coach Wilson: “To progress from the group it is a game we ultimately need to look to win.
“If we can beat them away it probably comes down to a winner takes all against Harlequins in January, but we are fully aware of the task ahead of us now in France.
“To go and beat the squad that Montpellier have at their place will be a big ask. But we have made good strides in recent weeks to get a far better performance.
“Over the last three games we have taken steps in the right direction. This is another huge challenge before we come back to two derby games so the games are coming thick and fast.
“They are tough games for us at the moment. But if we can keep players fit and be competitive then we can challenge for results.”
Montpellier: 15 Anthony Floch, 14 Julien Malzieu, 13 Timoci Nagusa, 12 Robert Ebersohn, 11 Marvin O'Connor, 10 Demetri Catrakilis, 9 Nic White, 8 Akapusi Qera, 7 Antoine Battut, 6 Fulgence Ouedraogo, 5 Paul Willemse, 4 Robins Tchale Watchou, 3 Jannie du Plessis, 2 Charles Geli, 1 Mikheil Nariashvili
Replacements: 16 Mickael Ivaldi, 17 Pat Cilliers, 18 Nicolas Mas, 19 Sitaleki Timani, 20 Wiaan Liebenberg, 21 Benjamin Lucas, 22 Anthony Tuitavke, 23 Pierre Berard
Cardiff Blues: 15 Rhys Patchell, 14 Alex Cuthbert, 13 Garyn Smith, 12 Rey Lee-Lo, 11 Tom James, 10 Jarrod Evans, 9 Tavis Knoyle, 8 Manoa Vosawai, 7 Josh Navidi, 6 Macauley Cook, 5 Lou Reed, 4 Jarrad Hoeata, 3 Taufa’ao Filise, 2 Kristian Dacey, 1 Gethin Jenkins (c)
Replacements: 16 Ethan Lewis, 17 Sam Hobbs, 18 Dillon Lewis, 19 James Down, 20 Josh Turnbull, 21 Lloyd Williams, 22 Tom Isaacs, 23 Blaine Scully
Date: Thursday, December 17
Venue: Altrad Stadium
Kick-off: 20:45 local (19:45 GMT)
Referee: Ian Tempest (England)
Assistant Referees: Greg Macdonald (England), Andrew Watson (England)
TMO: Trevor Fisher (England)