Ulster, who did the double over Bath in last season's tournament, will be hoping for more of the same this time around, with back-to-back fixtures against the English side in the run-up to Christmas.
Paddy Wallace returns at inside centre having recovered from the back niggle which ruled him out of last weekend's postponed match against the Newport Gwent Dragons.
Wallace will partner Nevin Spence in Ulster's midfield, with the 20-year-old starlet drafted in to make his full Heineken Cup debut. Spence replaces the injured Darren Cave (hamstring).
The third and final change in the back-line sees Springbok Ruan Pienaar get the nod at scrum half. Paul Marshall makes way, joining fellow backs Ian Whitten and David McIlwaine on the replacements bench.
Up front, Muller's return from the neck injury he sustained in Cardiff last month means that Tim Barker reverts to a bench role, while Stephen Ferris replaces Willie Faloon in a rejigged back row.
"So, this is a 'must win' to make sure that the next game is even bigger. Bath may have had a few problems this season - that's not for me to say - but they're always a difficult side to play against.
"They've got a great pedigree in this competition and we will be treating them as worthy opponents. They will be a very, very difficult side to beat."
With the match kicking off at 1.30pm, the Ravenhill gates will open at 12pm. Pitch heaters have been in operation for the past 36 hours, working to defrost the pitch and Ulster Rugby are confident that the fixture will go ahead.
Tickets for the match are still available to purchase and will be on sale tomorrow at the gates.
ULSTER (v Bath): Adam D'Arcy; Andrew Trimble, Nevin Spence, Paddy Wallace, Simon Danielli; Ian Humphreys, Ruan Pienaar; Tom Court, Nigel Brady, BJ Botha, Johann Muller (capt), Dan Tuohy, Stephen Ferris, Chris Henry, Pedrie Wannenburg.
Replacements: Andi Kyriacou, Paddy McAllister, Bryan Young, Tim Barker, Willie Faloon, Paul Marshall, Ian Whitten, David McIlwaine.