England internationals Sam Underhill and Ollie Lawrence have been ruled out of Bath's Champions Cup match against Castres at Stade Pierre-Fabre on Friday.

Flanker Underhill and centre Lawrence sustained "knocks" during Bath's 33-26 Prem win over Exeter on Saturday, with no detail on how long they could be out of action.

Miles Reid joins Ted Hill and last week's man of the match Alfie Barbeary in the back row, with Guy Pepper stepping down to the bench to take Underhill's place.

England international Max Ojomoh starts alongside Cameron Redpath in the centres having recovered from a calf injury.

Quinn Roux comes back into the starting line-up at the expense of Italian international Enoch Opoku-Gyamfi, who made his Prem debut against Exeter.

Every side in Pool Two has won one match after two rounds but Bath, who won the Challenge Cup last year after making an early Champions Cup exit, are the only one to have two bonus points and lead the way with six points.

Johann van Graan's side lost 45-34 to Toulon in their previous Champions Cup game, while Castres thrashed a much-changed Edinburgh side 33-0.

The top four sides after four matches will go through to the last 16 knockout stage.

Castres: Chabouni; Ambadiang, Karawalevu, Goodhue, Hulleu; Popelin, Fernandez; Walcker, Durand-Pradere, Collier, Ducat, Vanverberghe, Delaporte (capt), Cope, Ardron.

Replacements: Zarantonello, Sokobale, Corato, Staniforth, Meka, Doubrere, Herve, Palis.

Bath: Carreras; Arundell, Ojomoh, Redpath, Muir; Russell, Spencer (capt); Obano, Dunn, Sela, Roux, Molony, Hill, Reid, Barbeary.

Replacements: Tuipulotu, Van Wyk, Du Toit, Bayliss, Pepper, Carr-Smith, Butt, Cokanasiga.

Referee: Eoghan Cross (Ire)

Assistant referees: Andrew Cole (Ire) and Daniel Carson (Ire)

TMO: Leo Colgan (Ire)