There are four changes in total from the Leinster team that accounted for Munster in the PRO12 last weekend, with two in the backs and two in the forwards to take on Castres.
Rob Kearney continues at full-back as he wins his 180th cap with Zane Kirchner coming in on the right wing and Isa Nacewa again selected on the left wing and as captain.
Nacewa went over 500 points for Leinster last weekend with his two tries and late conversion. Having now scored 511 points, including 36 tries, he is fifth on the all time Leinster point scorer table.
Having made his debut last weekend in the Aviva Stadium, Robbie Henshaw will make his first start in the RDS Arena with Garry Ringrose outside him at 13.
In the half-backs, with Johnny Sexton feeling a tightness in his hamstring at training during the week, there is one change with Joey Carbery coming in for his European debut alongside Luke McGrath.
In the pack Jack McGrath comes into the front row alongside Sean Cronin and Tadhg Furlong.
McGrath will win his 100th cap for Leinster against Castres having made his debut in April 2010 against the Glasgow Warriors. As well as 99 Leinster caps, the 27 year old St Mary's club man has won 33 Ireland caps since his debut against Samoa in 2013.
In the back row there is one final change with Josh van der Flier coming in at open side. Rhys Ruddock continues at blind side with Jamie Heaslip again at number eight.
Heaslip will become the second most capped player in Leinster history when he lines out for his 222nd game and in doing so will become the most capped forward in Leinster history. Gordon D'Arcy on 261 is the player with the most Leinster appearances.
Meanwhile, Castres have made eight changes to their starting XV for their trip to Dublin.
Rory Kockott and Julien Dumora return in the half-backs, with Geoffrey Palis at full-back and Thomas Combezou named at outside centre.
An entirely new front row sees Antoine Tichit, Jody Jenneker and Daniel Kotze all start, with Mathieu Babillot the final change at blindside flanker.
Form: This will be the seventh meeting between the clubs in the competition, Leinster have won five of the previous six, including the last four in a row. The Irish province have won all three home games against Castres in the competition, restricting the French to single figures on each occasion. Leinster have won 19 of their last 21 home matches against Top 14 opposition (L2), although they lost their last such fixture against Toulon last season. Castres have never won in Ireland in the top flight, losing all nine away to Irish provinces. Leinster had the lowest lineout success last season on their own throw (79 percent), however, they averaged 2.3 steals per game on their opponents' throw, the joint highest rate in the competition.
Leinster: 15 Rob Kearney, 14 Zane Kirchner, 13 Garry Ringrose, 12 Robbie Henshaw, 11 Isa Nacewa (c), 10 Joey Carbery, 9 Luke McGrath, 8 Jamie Heaslip, 7 Josh van der Flier, 6 Rhys Ruddock, 5 Ian Nagle, 4 Devin Toner, 3 Tadhg Furlong, 2 Sean Cronin, 1 Jack McGrath
Replacements: 16 James Tracy, 17 Cian Healy, 18 Mike Ross, 19 Ross Molony, 20 Daniel Leavy, 21 Jamison Gibson-Park, 22 Cathal Marsh, 23 Noel Reid
Castres: 15 Geoffrey Palis, 14 Remi Grosso, 13 Thomas Combezou, 12 Robert Ebersohn, 11 David Smith, 10 Benjamin Urdapilleta, 9 Antoine Dupont, 8 Alex Tulou, 7 Steve Mafi, 6 Mathieu Babillot, 5 Rodrigo Capo Ortega (c), 4 Victor Moreaux, 3 Daniel Kotze, 2 Jody Jenneker, 1 Antoine Tichit
Replacements: 16 Brice Mach, 17 Mihaita Lazar, 18 Damien Tussac, 19 Thibault Lassale, 20 Anthony Jelonch, 21 Rory Kockott, 22 Maxime Javaux, 23 Florian Vialelle
Date: Saturday, October 15
Venue: RDS Arena
Kick-off: 15:15 local (14:15 GMT)
Referee: Matthew Carley (England)
Assistant Referees: Tim Wigglesworth (England), Steve Lee (England)
TMO: David Sainsbury (England)