Leinster Head Coach Leo Cullen has made 12 changes to his side for Saturday's clash with Ulster at the RDS Arena.
The clash sees third placed Leinster host fourth placed Ulster who are only five points behind the home side. Cullen makes a total of 12 changes from the side that played Munster last weekend, with a new pack starting in the RDS Arena.
In the backs, three players are retained but only outhalf Ross Byrne is again selected in the same position, Captain Isa Nacewa moves from the wing to full back, while Rory O’Loughlin moves from centre to the left wing.
Adam Byrne, who missed last week’s game in Thomond Park through illness, comes in on the right wing, with fellow UCD man Garry Ringrose coming into the centre. Noel Reid starts this week in the number 12 jersey having come off the bench last week.
Finally Luke McGrath partners Byrne in the half-backs.
In the pack it’s a new eight with an all-Irish international front row of Jack McGrath, Sean Cronin and Michael Bent starting. In the second row Devin Toner wins his 190th cap for Leinster beside Hayden Triggs. The back row sees Seán O’Brien, Josh van der Flier and Jamie Heaslip complete the starting XV.
Ulster boss Les Kiss has brought back Andrew Trimble for their PRO12 clash with Leinster at the RDS Arena on Saturday.
Paul Marshall, Darren Cave and Tommy Bowe, who were on the bench for the game versus Connacht last Friday, are also selected in the backline.
Marshall's inclusion at scrum-half will see Ruan Pienaar shift to fly-half, while Cave will partner Stuart McCloskey in midfield. Bowe and Trimble will be joined by Charles Piutau in the back three.
Forwards Rob Herring, Franco van der Merwe and Sean Reidy have also been promoted to the starting team, meaning Kiss has made seven personnel changes for the trip to Dublin.
Herring will captain the side from hooker and he will be joined in the front row by Andy Warwick and Rodney Ah You, both of whom have been retained from the win over Connacht.
Kieran Treadwell and Van der Merwe are paired in the second row, with Reidy joining Clive Ross and Roger Wilson in the back row.
With Wiehahn Herbst picking up a calf injury in training this week, tighthead prop Jonny Simpson is in line to make his first senior appearance if he's utilised from the bench. John Andrew and Callum Black are the other front row replacements. Pete Browne and Chris Henry will provide additional cover for the pack.
Brett Herron, Jacob Stockdale and Louis Ludik, who will make his 50th Ulster appearance if called upon, complete the match day 23.
Form: Leinster have lost two of their last three fixtures in the PRO12 but both losses were played away from home, in Llanelli and in Limerick. At the RDS Arena the Leinstermen have not been defeated since Toulon were the visitors in December 2015, whilst their most recent defeat at home in the PRO12 was to Newport Gwent Dragons in 2015. Ulster have won their last two matches in the PRO12, in Cardiff and at home to Connacht. Their two other victories on the road this season were at Treviso in round 2 and at Glasgow in round 4. The last six fixtures between the two provinces have all been won by the home side on the day, whilst Ulster’s only previous victory at the RDS Arena was 22-18 in March 2013.
Leinster: 15 Isa Nacewa (c), 14 Adam Byrne, 13 Garry Ringrose, 12 Noel Reid, 11 Rory O’Loughlin, 10 Ross Byrne, 9 Luke McGrath, 8 Jamie Heaslip, 7 Josh van der Flier, 6 Sean O’Brien, 5 Hayden Triggs, 4 Devin Toner, 3 Michael Bent, 2 Sean Cronin, 1 Jack McGrath
Replacements: 16 Richardt Strauss, 17 Andrew Porter, 18 Jeremy Loughman, 19 Mick Kearney, 20 Jack Conan, 21 Jamison Gibson-Park, 22 Tom Daly, 23 Zane Kirchner
Ulster: 15 Charles Piutau, 14 Andrew Trimble, 13 Darren Cave, 12 Stuart McCloskey, 11 Tommy Bowe, 10 Ruan Pienaar, 9 Paul Marshall, 8 Roger Wilson, 7 Sean Reidy, 6 Clive Ross, 5 Franco van der Merwe, 4 Kieran Treadwell, 3 Rodney Ah You, 2 Rob Herring, 1 Andy Warrick
Replacements: 16 John Andrew, 17 Callum Black, 18 Jonny Simpson, 19 Pete Brownwe, 20 Chris Henry, 21 Brett Herron, 22 Louis Ludik, 22 Jacob Stockdale
Date: Saturday, December 31
Venue: RDS Arena
Time: 15:00 local (15:00 GMT)
Referee: John Lacey (IRFU)
Assistant Referees: Frank Murphy, Joy Neville (both IRFU)
TMO: Peter Fitzgibbon (IRFU)