Jordan Larmour has been selected ahead of Rob Kearney while Johnny Sexton is ruled out through injury for Leinster and Ulster's Heineken Champions Cup quarter-final meeting on Saturday evening.
Their northern rivals, meanwhile, have Iain Henderson named in the second row, having recovered from injury this week.
For the hosts, the absence of their talismanic out-half is a key talking point. Sexton, the 2018 World Player of the Year, is coming off the back of a frustrating Six Nations campaign and will not be involved on Saturday.
Sexton is suffering with a leg injury, 'general tightness' according to his coach Leo Cullen.
There are four changes to the side which accounted for Wasps in the final pool game, with injuries ruling out Robbie Henshaw, Josh Van der Flier and Devin Toner, while Jamison Gibson-Park drops to the bench.
Selected in their place are Rory O'Loughlin, Sean O'Brien, Scott Fardy and Luke McGrath.
For Ulster, back in the knockout phase for the first time since 2014, Jordi Murphy starts at back-row, marking the first time he has played against his old side since his move.
He joins Marcell Coetzee and Nick Timoney in the back-row division.
Saturday's game, which kicks off at 5.45 in the Aviva Stadium, is the first time Irish provinces have met in the knockout phase of the competition since these two teams contested the Heineken Cup final in Twickenham in May 2012.
Leinster: Jordan Larmour, Adam Byrne, Garry Ringrose, Rory O'Loughlin, Dave Kearney; Ross Byrne, Luke McGrath; Cian Healy, Sean Cronin, Tadhg Furlong; Scott Fardy, James Ryan; Rhys Ruddock (c), Sean O'Brien, Jack Conan
Replacements: J Tracy, E Byrne, A Porter, M Kearney, D Leavy, J Gibson-Park, N Reid, R Kearney
Ulster: Michael Lowry, Robert Baloucoune, Darren Cave, Stuart McCloskey, Jacob Stockdale; Billy Burns, John Cooney; Eric O'Sullivan, Rory Best (c), Marty Moore; Iain Henderson, Kieran Treadwell; Nick Timoney, Jordi Murphy, Marcell Coetzee.
Replacements: R Herring, A Warwick, W Herbst, A O'Connor, S Reidy, D Shanahan, L Marshall, A Kernohan.
Referee: Romain Poite (France)
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