Pool one

Cardiff Blues v Gloucester, 3pm tomorrow, Sky Sports 2 , 1pm tomorrow, Sky Sports 2

Thomas O'Leary has recovered from an ankle injury that kept him out of Munster's last-gasp victory at home to Montauban and replaces Peter Stringer at scrum half. John O'Sullivan comes in at open-side flanker, shifting David Wallace to No8. Sale have to change the pack with Kristian Ormsby suspended for a week, but they have options and Sébastien Chabal moves to lock and Chris Jones comes in at blind-side flanker. Rudi Keil replaces the injured Lee Thomas at centre. Charlie Hodgson waits on the bench again.

Other match: Montauban v Clermont Auvergne, 3pm tomorrow

Pool two

Leinster v London Wasps, 5.30pm today, Sky Sports 2

Two unchanged sides after convincing, if not always fluent, victories. Josh Lewsey may not be doing his England prospects enormous good at centre, where he and Riki Flutey face Brian O'Driscoll. The only time that these sides have met was in the quarter-finals in 2006-07, when Wasps cruised to a 35-13 victory.

Castres v Edinburgh, 5.30pm today, Sky Sports 2 interactive

Castres signal some intent with Steve Kefu, the former Australia centre, returning along with Carl Hoeft, the former New Zealand prop. Edinburgh have lost their past 14 away games in this competition.

Pool three

Treviso v Leicester, 1.35pm today, Sky Sports 2 interactive

By surging into a ten-point lead away to Perpignan, Treviso showed the spirit of seasons past. Any back line organised by Fraser Waters, the former London Wasps midfield general, should be decent. With Ben Woods injured, Martin Corry moves from lock into the Leicester back row.

Ospreys v Perpignan, 3.30pm today, Sky Sports 2

Ospreys, who lost Jonathan Thomas, their Wales flanker to a groin injury, are also down to their fourth-choice scrum half, after Rhodri Wells suffered a shoulder injury. Rhys Webb comes in. Perpignan have lost both centres and are down to two backs on the bench.

Pool four

Stade Français v Scarlets, 1.35pm today, Sky Sports 2

After their Stradey Park farewell was ruined by Harlequins last Saturday, Scarlets' hopes could go up in smoke with another loss today. Injuries to Vernon Cooper and Simon Maling, the locks, soured the defeat. Dominic Day and Scott MacLeod step into bigger boots. After their first win at their fifth attempt away to Ulster, Stade make just one change, at centre.

Harlequins v Ulster, 3pm today

After his impact off the bench against the Scarlets, Nick Easter replaces Tom Guest at No8. Ugo Monye moves to centre and Tom Williams goes on to the wing. Timoci Nagusa, the Fiji wing, comes in for Ulster.

Pool five

Bath v Newport Gwent Dragons, 1pm tomorrow, Sky Sports 2 interactive

Both sides are unchanged from last weekend and the Dragons cross the Severn Bridge after a 32-22 victory at home to Glasgow. But Bath have a point to prove after losing with the last kick of the game away to Toulouse. Bath should have too much pace in their back row for the Dragons, for whom Colin Charvis, the skills coach, starts again. Lee Mears, the Bath hooker, who has just signed a four-year contract, is in for a good workout against his opposite number, Tom Willis. Shontayne Hape, the former Bradford Bulls and New Zealand rugby league player, may make his Heineken Cup debut for Bath off the bench.

Pool six

Cardiff Blues v Gloucester, 3pm tomorrow, Sky Sports 2

Both 22s are unchanged after victory last weekend. On the large playing surface at the Millennium Stadium, Ryan Lamb's tactical kicking will be under scrutiny. Olly Barkley may share that responsibility and should have a muscular confrontation with Tom Shanklin at inside centre. Cardiff must win again if they are serious about qualifying. Gloucester must react quickly to Alain Rolland, who is usually more laissez faire at refereeing the ruck, where Martyn Williams, the Blues and Wales flanker, is highly effective at slowing ball.

Other match: Biarritz v Calvisano, 5pm today