Number eight Anthony Foley and outside backs John Kelly and Anthony Horgan have all been included in the squad, having recovered from recent injuries.
New signing Brian Carney, who scored a try in last Friday's 24-21 Magners League comeback win at Ulster, has also made the cut, as well as Shannon lock Donnacha Ryan, who is one of three extra players Munster have registered for the competition's knockout stages.
The Munster squad trained earlier today at Musgrave Park in Cork, with O'Connell watching on from the sidelines.
Friday's quarter-final tie at Stradey Park, the first ever European meeting between the Celtic rivals, has a 7.30pm kick-off. Sky Sports 3 will broadcast the game live while IrishRugby.ie will also be running a live match tracker.
MUNSTER Squad (v Llanelli) - Backs (13): Christian Cullen, Brian Carney, Ian Dowling, Anthony Horgan, Trevor Halstead, Eoghan Hickey, John Kelly, Lifeimi Mafi, Barry Murphy, Jeremy Manning, Ronan O'Gara (capt), Tomas O'Leary, Peter Stringer.
Forwards (15): Tony Buckley, Jerry Flannery, Anthony Foley, Marcus Horan, John Hayes, Denis Leamy, Donncha O'Callaghan, Mick O'Driscoll, John O'Sullivan, Federico Pucciariello, Alan Quinlan, Donnacha Ryan, Frankie Sheahan, Chris Wyatt, David Wallace.