O'Leary sustained what was described as a "slight" hamstring strain in training and was not considered as "a precautionary measure". However, a Munster spokesperson insisted that O'Leary remains in contention for a place in the Heineken Cup semi-final against Leinster tomorrow week.
Ronan O'Gara, Jeremy Manning, Marcus Horan and Denis Leamy are other notable absentees for tonight's crucial tie.
There is continued concern about Horan, whose damaged calf muscle is only responding slowly to treatment, and Leamy, who has been handicapped by an ankle sprain since the Ireland-England Triple Crown battle. Federico Pucciarello stands in for Horan and Mick O'Driscoll takes over at number six from Leamy.
Coach Declan Kidney has given the broadest hint yet that John Kelly will wear the number 13 jersey in tomorrow week's trip to Lansdowne Road. Kelly has been moved from wing to centre, with his Cork Con teammate Anthony Horgan, largely out of favour since Christmas, recalled to the wing.
Horgan is more at home on the left wing which is now the preserve of Ian Dowling but at least he has been given a chance to prove his form in the build-up to the Leinster clash.
The hosts can't afford a fourth successive defeat if they are to challenge for the Celtic League title, and what goes with it in the context of Heineken Cup seeding. In recent weeks, they have lost to Glasgow (26-20) at Thomond Park and away to the Newport Gwent Dragons (23-17) and Ulster (27-3). Going into this 18th round of matches they were seven points behind leaders Leinster and five behind Ulster.
Edinburgh coach Todd Blackadder, who has also seen his team lose their last three matches, makes five changes from the side that conceded two intercept tries in their 21-10 defeat by Cardiff at Murrayfield eight days ago. Hooker Dougie Hall has been sidelined with a shoulder injury so prop Craig Smith, who makes his 150th appearance for the club tonight, provides cover for Andrew Kelly. Francisco Leonelli returns on the right wing for Chris Paterson, who is rested. Marcus Di Rollo is reinstalled at outside centre as Peter Jorgensen takes the No 12 jersey. Alasdair Dickinson joins the front row for Dave Hewett while Alasdair Strokosch starts at openside flanker.
Blackadder said: "Munster will provide a huge challenge but we've a good game plan and we'll give them a go."
Before being ruled out, O'Leary admitted last week's defeat to the Dragons was a setback for Munster.
"That knocked us back a bit in terms of our Celtic League chances, but the title is still there to be won. We just have to make sure we beat Edinburgh, and with that out of the way, concentrate on the Leinster game. "It's going to be a long but very exciting week."
- S. Payne; A. Horgan, J. Kelly, T. Halstead, I. Dowling; P. Burke, P. Stringer; F. Pucciarello, J. Flannery, J. Hayes, D. O'Callaghan, P. O'Connell, M. O'Driscoll, D. Wallace, A. Foley (capt).
: F. Roche, D. Fogarty, T. Hogan, J. O'Sullivan; M. Prendergast, M. Lawler, R. Henderson.
: - H. Southwell; F. Leonelli, M. Di Rollo, P. Jorgensen, S. Webster; D. Hodge, M. Blair; A. Dickinson, A. Kelly, C. Smith, A. Kellock, S. Murray (capt), A. Hogg, A. Strokosch, S. Taylor.
: A. Jacobsen, D. Hewett, D. Duley, A. MacDonald; R. Lawson, P. Godman, N. De Luca.