Munster, out of the Celtic League reckoning, meet Edinburgh in the competition at Musgrave Park tomorrow night but Gaffney will be fielding only four of the starting line-up from the victory over Stade Francais at the weekend.
Those four are all backs: Christian Cullen, Shaun Payne, John Kelly and Rob Henderson.
Kelly plays away from his usual wing position when he partners Henderson in the centre. One of the substitutes last weekend, Anthony Horgan, returns to the side.
Wasps number eight Lawrence Dallaglio has been declared fit to play against Munster in their Euro semi-final at Lansdowne Road.
The England captain underwent a precautionary brain scan yesterday after suffering a sickening clash of heads with team-mate Paul Volley in the Euro quarter-final victory over Gloucester. The back rowers collided in the early stages of the first half and both required treatment for five minutes before resuming.
"Everything was fine in the scan," said a Wasps spokesman yesterday.
"There was nothing wrong and he has returned to training.
"Both Dallaglio and Volley will be available for action at the weekend if selected to play."
This is a major boost for Warren Gatland's Wasps, who face Leeds in the a crucial Zurich Premiership League match on Sunday afternoon.
Dallaglio said after the match: "There are two heads you don't want to collide with at this club one is Trevor Leota's and the other is Paul Volley's."
Harlequins coach Mark Evans is adamant his side must go to Galway in a fortnight looking for a victory, despite taking a nine-point lead into the second leg of their Parker Pen Challenge Cup semi-final against Connacht.
Quins outscored their Irish opponents by four tries to one in their 31-22 victory but Evans warned: "They are a very good side. You don't beat Pau, Narbonne and Beziers if you are a bunch of muppets.
"I don't think Connacht have been given the credit they deserve."
Quins fell foul of Italian referee Giulio de Santis and Evans added: "At one stage the penalty count was 17-6 against us which is unusual given that we had most of the play, but that's part of the competition.
"You play against teams you don't normally play against and you play with officials you don't normally come across. I thought the referee had areasonably good game up to half-time but I think he wandered a bit in the second half."
Tickets for the semi-final of the Heineken Cup between Munster and Wasps go on sale this morning at 9.30am.
They can be purchased from the following outlets:
Thomond Park, Limerick (Munster Branch IRFU Office).
Musgrave Park, Cork, (Munster Branch IRFU Office).
Lansdowne Road, Dublin, (62 Lansdowne Road, IRFU Office).
Ticketmaster, Stephens Green, Dublin; Ticketmaster, Empire Music, Limerick.
Spar Shop, Donnybrook; Spar Shop, Bath Avenue; Active Sports, Blackrock Shopping Centre; Elvery's, Suffolk Street; Elvery's, Dawson Street.
Tickets prices will range from €23 (terrace), €36 (goal-line) €43 (touchline).
: C. Cullen, S. Payne, J. Kelly, R. Henderson, A. Horgan, J. Holland, E. Reddan, F. Roche, J. Flannery, G. McIlwham, T. Hogan, D. Pusey, S. Keogh, P. Malone, C. McMahon. Replacements: R. Callaghan, M. Cahill, T. Hayes, M. Melbourne, F. Murphy, C. O'Sullivan.