Pool One
Defeat by Toulouse at the RDS would leave holders Leinster needing to be one of the best three runners-up to qualify for the knockout stage. They are without five Ireland internationals for the visit of the club whose record of four European Cup final victories they equalled last season. Fly-half Johnny Sexton is among them, sidelined by a knee injury. Toulouse have lost only two matches all season and none in Europe. Wales’ No 8 Taulupe Faletau returns for Bath after three months out with a broken arm as they host Wasps at the Rec with avoiding finishing bottom on their minds.
Leinster v Toulouse Sat 1pm
Bath v Wasps Sat 3.15pm (GMT)
Pool Two
Exeter failed to secure a victory in the opening three rounds but they still have a chance of making the quarter-finals. Joe Simmonds, who made an impact off the bench in the hard-fought victory over Bristol last weekend, replaces Gareth Steenson at fly-half with the Chiefs needing the garnish of a try bonus point before their final match against Munster at Thomond Park. Castres, the French champions, started the round second in the group but their away record in Europe is dismal, only four victories in 15 Champions Cup campaigns.
Exeter v Castres Sun 1pm
Pool Three
Saracens will qualify for the last eight if they win in Lyon; the hosts have yet to pick up a point in their first European Cup. Maro Itoje returns for his first appearance since the beginning of December after recovering from a knee injury and Jamie George is back at hooker after being rested last weekend. Lyon lost at home to Cardiff Blues and Glasgow in previous rounds but in the Top 14 they average 38 points a match. Glasgow start the weekend four points behind Saracens and welcome back Stuart Hogg for their home fixture against Cardiff.
Glasgow v Cardiff Blues Sun 3.15pm
Lyon v Saracens Sun 3.15pm
Resurgent Toulouse leading the French rugby renaissance | Robert Kitson
Pool Four
Racing went into the round with the most points of any team, 19, but their unbeaten record will be tested at Ulster, whose only home defeat this season was by Connacht. Last season’s beaten finalists Racing include Simon Zebo and Finn Russell in their lineup. Rory Best leads Ulster who are on course to reach the quarter-finals for the first time since 2014. The Scarlets, who made the semi-finals last season, are looking for their first victory in the group. Hooker Ken Owens continues at No 8 for the visit of Leicester, who have rested their England backs Jonny May, Manu Tuilagi and George Ford, while Ben Youngs is a replacement.
Ulster v Racing 92 Sat 3.15pm
Scarlets v Leicester Sat 5.30pm
Pool Five
Richard Cockerill’s Edinburgh have been the surprise of the tournament, on course to progress from the group stage for only the third time. If they win in Toulon, they would be all but through and they field the side that won in Glasgow after Christmas. Newcastle’s European promise turned sour after consecutive defeats by Edinburgh last month but they still have a mathematical chance of reaching the quarter-finals. They are in Montpellier, who have yet to recover from their shock defeat by Castres in last season’s Top 14 final but could finish the weekend top of the group.
Montpellier v Newcastle Sat 1pm
Toulon v Edinburgh Sat 5.30pm