"Tomas has shown tremendous professionalism and dedication in getting himself back playing and great credit is due to him and to the work done by our medical and fitness staff. It is of course great to see him back in the squad particularly after the injury he sustained."
O'Leary was not named in the extended squad but Peter Stringer had picked up a calf strain in the game against Cardiff Blues and that did not respond well enough to treatment during the week to allow him make the trip. Toby Morland will partner his old school mate Jeremy Manning in Parc Y Scarlets.
Coach Tony McGahan retains 21of the 22 that saw duty against the Blues, Marcus Horan missing out this time with French international prop Julien Brugnaut coming into the front row.
Elsewhere, McGahan changes things around ever so slightly with Damien Varley starting on this occasion ahead of Denis Fogarty whom he replaced in the Blues game.
Munster: F Jones; D Howlett, B Murphy, L Mafi, D Hurley; J Manning, T Morland; J Brugnaut, D Varley, J Hayes; D Ryan, M O'Driscoll (capt); A Quinlan, N Ronan, D Leamy. D Fogarty, T Buckley, B Holland, T O'Donnell, T O'Leary, S Deasy, T Gleeson.