In addition to that trio from the starting XV last weekend, Christian Cullen twinged a hamstring in training while Denis Fogarty sustained a hand injury ruling both of them out of the Dragons match.
Fogarty and Cullen are likely to be available for the Edinburgh game but Horan will not, management hoping to have the prop back in time for the Heineken Cup semi-final clash with Leinster.
Munster ( v Newport-Gwent Dragons). S Payne; J Kelly, T O'Leary, T Halstead, I Dowling; J Manning, P Stringer; F Pucciariello, J Flannery, J Hayes; D O'Callaghan, P O'Connell; M O'Driscoll, D Wallace, A Foley capt.
Replacements: F Roche, E McGovern, S Keogh, J O'Sullivan, P Burke, M Mullins, R Henderson,