Jack Crowley has been ruled out of Munster’s Champions Cup pool opener at Bath on Saturday night with an ankle injury as Clayton McMillan makes five changes to the side that faced the Stormers last weekend, including a debut for new signing Michael Ala’alatoa.

Ireland fly-half Crowley sustained an ankle injury in the opening seconds of last Saturday’s top of the table URC clash with the South African franchise, as flanker Paul de Villiers followed through on his attempt to charge down a clearing kick. 

The 25-year-old played through the initial pain and played the full 80 minutes of his side’s 27-21 loss, Munster’s first of the campaign under their new head coach.

Yet having missed training early in the week, Crowley has been replaced at number 10 by JJ Hanrahan as Munster go to the home of Johann van Graan’s English champions.

There is one further backline change with summer signing Dan Kelly in at inside centre as Alex Nankivell moves to the bench to take the former Leicester midfielder’s place as outside backs replacement. 

And in the pack loosehead prop Michael Milne rotates off the bench to replace Jeremy Loughman, who moves the other way while in the second row, Jean Kleyn returns from international duty with South Africa to partner Tom Ahern as Fineen Wycherley misses out for the first time this season.

There is an enforced switch in the back row as Jack O’Donoghue continues his return to play protocols following a failed Head Injury Assessment against the Stormers, with his replacement that night John Hodnett moving into the openside flanker role alongside captain Tadhg Beirne on the blindside and Gavin Coombes at No.8.

Hanrahan will partner scrum-half Craig Casey in the half-backs, with Kelly pairing up with Tom Farrell in midfield and there is an unchanged back three of wings Diarmuid Kilgallen and Thaakir Abrahams, and full-back Shane Daly.

Former Leinster prop Ala’alatoa is set for his Munster debut as replacement tighthead, covering for John Ryan having returned to Ireland from Clermont Auvergne until the end of the season, while one of two covering back rowers is fit-again Alex Kendellen, who is set for his first appearance since the URC round one win over Scarlets in September.

Hooker Lee Barron, Loughman and Ala’alatoa fill the front row bench back-up with Edwin Edogbo, Ruadhán Quinn and Kendellen completing the forward cover. 

Barron, Edogbo and Quinn are all in line for their Champions Cup debuts from a bench split of six forwards while the two backline replacements are scrum-half Ethan Coughlan and Nankivell.

Munster said Crowley, and wings Calvin Nash (shoulder) and Andrew Smith (knee/hamstring) were each estimated to return to play in one to two weeks, with their team set to return home for a first Champions Cup pool tie at Supervalu Pairc ui Chaoimh against Gloucester a week on Saturday.

The task immediately in front of Munster, however, is a formidable Bath line-up named on Friday by head coach of the current PREM leaders van Graan. The west country side have strength in depth with stars of the ilk of Springbok tighthead Thomas du Toit, England forwards Ted Hill and Sam Underhill and former Leinster lock Ross Molony, as well as Argentina star playmaking back Santi Carreras all named on the bench.

Scotland and Lions fly-half Finn Russell starts at 10 in half-back partnership with captain and England scrum-half Ben Spencer while English standouts from November Max Ojomoh and Guy Pepper start at outside centre and openside flanker respectively.

This is a challenge to provide an immediate gauge of just how much progress Munster have made under their new boss McMillan.

BATH: Tom de Glanville; Joe Cokanasiga, Max Ojomoh, Cameron Redpath, Henry Arundell; Finn Russell, Ben Spencer – captain; Beno Obano, Tom Dunn, Will Stuart; Quinn Roux, Charlie Ewels; Josh Bayliss, Guy Pepper, Miles Reid.

Replacements: Kepu Tuipulotu, Francois van Wyk, Thomas du Toit, Ross Molony, Ted Hill, Tom Carr-Smith, Santi Carreras, Sam Underhill.

MUNSTER: Shane Daly; Diarmuid Kilgallen, Tom Farrell, Dan Kelly, Thaakir Abrahams; JJ Hanrahan, Craig Casey; Michael Milne, Diarmuid Barron, John Ryan; Jean Kleyn, Tom Ahern; Tadhg Beirne (C), John Hodnett, Gavin Coombes.

Replacements: Lee Barron, Jeremy Loughman, Michael Ala’alatoa, Edwin Edogbo, Ruadhán Quinn, Ethan Coughlan, Alex Nankivell, Alex Kendellen.