Pienaar will play his landmark game alongside Paddy Jackson at half back, with Stuart McCloskey and Darren Cave continuing their midfield partnership. Nelson is joined in the back three by Craig Gilroy and Andrew Trimble.
Iain Henderson will start at lock for Ulster for the first time this season, following his appearance in the back row last weekend. He will combine with fellow Ireland international Dan Tuohy in the second row, with Franco van der Merwe earning a break.
McCall will have captain Rory Best and Wiehahn Herbst beside him in the front row, while the loose forward trio is made up of Diack, Reidy and number 8 Nick Williams.
Kiss has once again opted to freshen up the replacements bench, with Chris Henry providing vital experience alongside Rob Herring, Roger Wilson, Paul Marshall, Ian Humphreys and Louis Ludik. Andrew Warwick and Ricky Lutton will provide cover for the front row players.
The match will be televised live on BBC2 NI.
Ulster team & replacements to face Leinster, Guinness PRO12, RDS, Friday 27th November (kick off 7.35pm):
(15-9): Peter Nelson, Andrew Trimble, Darren Cave, Stuart McCloskey, Craig Gilroy, Paddy Jackson, Ruan Pienaar;
(1-8): Kyle McCall, Rory Best (captain), Wiehahn Herbst, Iain Henderson, Dan Tuohy, Robbie Diack, Sean Reidy, Nick Williams;
Replacements (16-23): Rob Herring, Andrew Warwick, Ricky Lutton, Roger Wilson, Chris Henry, Paul Marshall, Ian Humphreys, Louis Ludik.
