Bayonne and Harlequins are neck-and-neck at the top of Pool one as the English visit Prato and the Basques host Connacht.
Cavalieri v Harlequins
Although Quins and Bayonne have an equal number of wins behind them, Bayonne top pool 1 (with Quins in 2nd place) by just one point, and the London club will know that Saturday's clash against Cavalieri Prato will be a must win game if they are to stay in the hunt for a place in the knock out stages.
Quins are unbeaten in their last 5 matches in all competitions.
Ugo Monye, who was born in London, came through the Quins academy system and went on to represent Quins, England and the British and Irish Lions, makes his 150th appearance at Stadio Lungovicenzio.
Cavalieri : 15 Rima Wakarua, 14 Martin Murgier, 13 Winston Mafi, 12 Clemens Von Grumbkov, 11 NiccolÃ² Tempestini, 10 Billy Ngwaini, 9 Pino Patelli, 8 Noa Soqueta, 7 Filippo Cristiano, 6 Luca Petillo, 5 Wouter Moore, 4 Luca Beccaris, 3 Gabriel Bocca, 2 Lorenzo Giovanchelli, 1 Leandro Poloni
Replacements:16 Alessio Neri, 17 Gerlando Marino, 18 Alessandro Borsi, 19 Nicola Belardo, 20 Stefano Canale, 21 Alberto Chiesa, 22 Filippo Vezzosi, 23 Filippo Cazzola
Harlequins:15 Tom Williams, 14 Sam Smith, 13 Tom Casson, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Rory Clegg, 9 Danny Care, 8 Tom Guest, 7 Will Skinner, 6 Maurie Fa'asavalu, 5 George Robson, 4 Tomas Vallejos, 3 Mark Lambert, 2 Chris Brooker, 1 Joe Marler.
Replacements:16 Matt Cairns, 17 Rob Buchanan, 19 Peter Browne, 20 Chris Robshaw, 21 Karl Dickson, 22 Nick Evans, 23 Gonzo Camacho,
Date: Saturday, January 15
Venue: Stadio Lungobisenzio, Prato
Kick-off: 15.00 (14.00 GMT)
Referee: Tim Hayes
Bayonne v Connacht:
The Connacht team sees a number of changes to the team that narrowly lost to the Dragons last week at Rodney Parade.
There is also a number of positional changes in a re-jigged team. Head Coach Eric Elwood hopes the switches will give his side the spark needed to re-ignite Connacht's season.
There is only two changes in the pack with Bernie Upton replacing Michael Swift and Mike McComish returning to reclaim the number eight jersey.
Eoin Griffin is the only player to remain in a new backline that sees former Blackrock College winger Shane Monahan come in on the right wing with Brian Touhy coming in on the left. Frank Murphy and Ian Keatley return at halfback and Niva Ta'auso returns to the centre, this time at 12, which allows Fionn Carr to line out at full-back.
Second Row Mike McCarthy will earn his 100th cap for Connacht this weekend, the 29 year old joined Connacht in 2003 and has had spells with London Wasps and Newcastle Falcons and has been ever present in the Connacht side since returning in 2007.
Meanwhile, Bayonne have named a very strong side including prolific fly-half Benjamin Boyet. SÃ©bastien FauquÃ© moves from 10 to 12.
Former Stormers full-back Joe Pietersen features on the wing while Tonga Lea'aetoa adds grnut to the front row.
Bayonne: 15 Pepito Elhorga, 14 Garth Ziegler, 13 Thibault Lacroix, 12 Sebastien Fauque, 11 Johnan Pietersen, 10 Benjamin Boyet, 9 Julien Audy, 8 Marc Baget, 7 Dwayne Haare, 6 Guillaume Bernad, 5 Cameron Treloar, 4 Robin Linde, 3 Denis Avril, 2 Arnaud Heguy, 1 Tonga Lea'aetoa.
Replacements:16 Francois Da Ros, 17 Pierre Philippe Lafond, 18 Walter Desmaison, 19 Ross Filipo, 20 Jean-Jo Marmouyet, 21 Francois Carillo, 22 Cedric Garcia, 23 Sam Gerber
Connacht: 15 Fionn Carr, 14 Shane Monahan, 13 Eoin Griffin, 12 Niva Ta'auso, 11 Brian Tuohy, 10 Ian Keatley, 9 Frank Murphy,8 Mike McComish, 7 Jonny O'Connor, 6 Andrew Browne, 5 Mike McCarthy, 4 Bernie Upton, 3 Jamie Hagan, 2 Sean Cronin, 1 Brett Wilkinson.
Replacements:16 Adrian Flavin, 17 Rodney Ah You, 18 Ronan Loughney, 19 Shane Connelly, 20 Michael Swift, 21 Cillian Willis, 22 Keith Matthews, 23 Miah Nikora
Date: Saturday, January 15
Venue: Stade Jean Dauger, Bayonne
Kick-off: 20:45 (19.45GMT)
Referee: Peter Allan