For Bath, Lions and England backs Mike Catt and Matt Perry are expected to return following hamstring problems, whilst Iain Balshaw suffered no reaction after coming back from a shoulder injury.
USA Eagles back rower Dan Lyle is also available for the first time since January following shoulder surgery.
Alessio Galasso (ankle), and Lee Mears (hamstring) were not considered.
"Balsh will definitely start the game, whilst we will be making last-minute calls on Mike Catt and Matt Perry," said Bath co-coach Brian Smith. "Dan Lyle though, is back and has been making strides."
For Shoguns, captain and lock Garath Archer is available for selection after a successful appeal against a yellow card, but coach Peter Thorburn is without blindside flanker Matt Salter, who injured his neck on Tuesday night against Saracens.
The 26-year-old Salter suffered soft tissue damage to his neck, but has not picked up any long-term damage.
Thorburn has added centres Martin Shaw and Andrew Higgins as well as back rowers Chris Morgan and Matt Styles to his match-day squad.
Said Thorburn on bristolshoguns.co.uk: "Ashton Gate is a great surface and it is going to be a superb environment for us to play in front of a record Premiership crowd. We know that the thousands of Bristolians attending the game will get behind us."
Commenting on any possible disruptions caused by Thursday's announcement that "exploratory discussions" of a merger had been held with Shoguns, Bath co-coach Smith insisted that his side would remain fully focused on the job at hand.
"We have faced a lot of challenges this season, but the playing group is very strong and the game against Bristol is yet another massive challenge for us," said Smith, who shares the coaching duties with former Wallaby hooker Michael Foley.
"The timing of this news is less than ideal, but it goes without saying that this game at the weekend is nothing other than a very fierce battle.
"You would be kidding yourself to think that either team would be going into this thinking that it does not really matter. There is a lot of pride at stake and we want to stay alive in the Zurich Premiership by our own right."
Bath (squad, 22):
Forwards: David Barnes, Andy Beattie, Steve Borthwick, Danny Grewcock (captain), Jonathan Humphreys, Andy Long, Dan Lyle, John Mallett, James Scaysbrook, Matt Stevens, Gavin Thomas, Nathan Thomas.
Backs: Iain Balshaw, Olly Barkley, Ross Blake, Mike Catt, Gareth Cooper, Kevin Maggs, Matt Perry, Elvis Seveali'i, Mike Tindall, Tom Voyce.
Bristol Shoguns (squad, 25): Paul Johnstone, Andrew Sheridan, Saul Nelson, Emiliano Bergamaschi, Richard Skuse, Garath Archer (captain), Scott Morgan, Alex Brown, Michael Lipman, Rhys Oakley, Craig Short, Chris Morgan, Matt Styles, Agustin Pichot, Paul Hodgson, Shane Drahm, Lee Best, Matt Carrington, Felipe Contepomi, Daryl Gibson, Phil Christophers, Andrew Higgins, Martin Shaw, David Rees, Brendon Daniel.
Kick-off: 15.00 BST (14.00 GMT)