In all Gaffney has made nice changes to last weeks losing side, bringing International stars Ronan O'Gara, Peter Stringer and Paul O'Connell return, but openside flanker Denis Leamy keeps David Wallace on the bench.
The Scarlets have made one change to the side that beat Edinburgh.
Gareth Bowen has come in for Arwel Thomas at fly-half, but coach Gareth Jenkins has delayed naming his replacements as he assesses fitness.
'There is a great tradition at Thomond Park and with their internationals back we will see Munster in their true guise,' Jenkins told BBC Sport Wales. 'We have to create an environment to put them under pressure. We need a positive scrum, aggressive line-out, a stubborn tackling game and enough flair in our own play.'
The Scarlets did the double over Munster on their way to the Celtic League title last season, Bowen starring in a 19-12 victory at Thomond Park last September.
Munster: C Cullen; J Kelly, M Mullins, R Henderson, A Horgan; R O'Gara, P Stringer; M Horan, F Sheahan, J Hayes, D O'Callaghan, P O'Connell, A Quinlan, D Leamy, A Foley
Replacements: G McIlwham, J Flannery, T Hogan, D Wallace, M Prendergast, P Burke, J Storey
Scarlets: B Davies; G Evans, M Watkins, M Taylor, T Selley; G Bowen, M Phillips; I Thomas, M Rees, J Davies, V Cooper, A Jones, S Easterby (capt), G Thomas, A Powell
Referee: Malcolm Changleng (Scotland)