Tony McGahan's extended squad includes fit-again captain Paul O'Connell who is poised to make his first Heineken Cup appearance since last season's pool stages.
Tom Gleeson, Scott Deasy and Doug Howlett are pushing for selection in the backs division after missing last weekend's 16-9 victory over the Cardiff Blues in the Magners League.
Darragh Hurley, Ryan and James Coughlan are the forwards added to the panel that moved Munster four points clear at the top of the league table.
Previewing Sunday's showdown with the reigning league champions, Howlett said: "It is still early days as far as qualification for the quarter-finals goes and everyone in our pool is in with a hand so the next two weekends are vital.
"In my short experience in the Heineken Cup, these back-to-back games can either break you or make you and I certainly want to experience another tournament final.
"I have played a fair few games both with and against Jerry (Collins) and Marty (Holah) and it is clear to everyone that they have had a huge effect on the Ospreys.
"They are fantastic players and it is certainly no surprise to me that they are doing so well at the Ospreys. Collectively, the Ospreys have one of the best squads in Europe - you just have to look at the names on the teamsheet to see just how strong their squad is.
"We know we are in for two huge matches against them and that we are really going to have to be at the top of our game home and away."
The former All Black winger added: "Of course we have missed Paul (O'Connell), he is such a key player and such an influential figure for any team - be it Munster, Ireland or the Lions.
"However, he is a real professional and has stayed fully involved with the team, doing everything he can to be of value while he has been recovering from his injury. I know he is just itching to get back (playing Heineken Cup rugby) for Munster."
The Munster matchday 23 will be confirmed on Friday afternoon.
MUNSTER Squad (v Ospreys) - Backs (12): Tomas O'Leary, Peter Stringer, Ronan O'Gara, Paul Warwick, Johne Murphy, Lifeimi Mafi, Tom Gleeson, Scott Deasy, Denis Hurley, Sam Tuitupou, Keith Earls, Doug Howlett.
Forwards (16): Wian du Preez, Damien Varley, Mike Sherry, Darragh Hurley, John Hayes, Tony Buckley, Dave Ryan, Donncha O'Callaghan, Paul O'Connell, Mick O'Driscoll, Donnacha Ryan, James Coughlan, David Wallace, Alan Quinlan, Niall Ronan, Denis Leamy.