Leamy picked up an ankle injury in the final Six Nations match against England and is consdered slightly better than 50/50 by coach Declan Kidney to be fit for consideration for the match day squad while Manning returns to the squad having recovered from an arm injury sustained in mid January.
Save for some game time last week against Leinster A and Midleton, Cullen has not seen competitive action since March 2005, Mullins has been out since August - he too played against Leinster A - while Henderson's season has been dogged by injury.
Munster trained this (Tuesday) afternoon in Thomond Park and will complete their preparation with a training session in Cork on Thursday followed by a Captain's Run in Lansdowne Road on Friday after they arrive in Dublin.
The match day 22 will be announced on Friday at 12 noon.
Munster Squad: C Cullen, S Payne, J Kelly, M Mullins, R Henderson, T Halstead, I Dowling, J Manning, R O'Gara, T O'Leary, P Stringer, M Horan, J Hayes, F Pucciariello, J Flannery, D Fogarty, P O'Connell, D O'Callaghan, T Hogan, M O'Driscoll, D Leamy, J O'Sullivan, D Wallace, S Keogh, A Foley.