The only other change in personnel is in the front row where South African prop Wian du Preez replaces Dave Kilcoyne on the loosehead side of the scrum.
Dineen gets his chance as Keith Earls' recovery from injury prevented him taking a full part in training this week. Earls has been named on the replacements bench along with fellow Ireland internationals Damien Varley, Donncha O'Callaghan and Tomas O'Leary.
It will be a last Thomond Park appearance for Mafi and O'Leary, both of whom depart these shores at the end of the season for pastures new.
The prize for a Munster win is a trip to the Liberty Stadium a week from now for a semi-final joust with tthe Ospreys.
Glasgow Warriors, who are at home to Connacht on Saturday, are odds on to provide table toppers Leinster with their semi-final opposition next week.
MUNSTER (v Ulster): Felix Jones; Johne Murphy, Ivan Dineen, Lifeimi Mafi, Simon Zebo; Ian Keatley, Conor Murray; Wian du Preez, Mike Sherry, BJ Botha, Mick O'Driscoll, Paul O'Connell (capt), Donnacha Ryan, Tommy O'Donnell, Peter O'Mahony.
Replacements: Damien Varley, Dave Kilcoyne, Stephen Archer, Donncha O'Callaghan, Paddy Butler, Tomas O'Leary, Scott Deasy, Keith Earls.