Ruddock is set to start wearing the number six jersey, with Dominic Ryan making a positional switch to number seven. Shane Jennings will start among the replacements and is just two games away from his 200th Leinster appearance. Last Saturday's man of the match, Jamie Heaslip, completes the back row and will captain Leinster.
The rest of the front eight are as you were from last weekend. Devin Toner and Mike McCarthy start in the second row, with a front three of Jack McGrath, Sean Cronin and Mike Ross.
Rob Kearney and Darragh Fanning start in the back three for the second match in a row, with Fergus McFadden coming in to replace Zane Kirchner who will be out for two to three weeks.
There are no changes in midfield or in the half-backs. Ian Madigan starts at inside centre, Brendan Macken at outside centre, Jimmy Gopperth at out-half and Isaac Boss at scrum-half.
Gordon D'Arcy is named in a Leinster squad for the first time this season, starting from the bench.
LEINSTER
15. Rob Kearney
14. Fergus McFadden
13. Brendan Macken
12. Ian Madigan
11. Darragh Fanning
10. Jimmy Gopperth
9. Isaac Boss
1. Jack McGrath
2. Sean Cronin
3. Mike Ross
4. Devin Toner
5. Mike McCarthy
6. Rhys Ruddock
7. Dominic Ryan
8. Jamie Heaslip CAPTAIN
Replacements
16. Bryan Byrne
17. Cian Healy
18. Tadhg Furlong
19. Tom Denton
20. Shane Jennings
21. Eoin Reddan
22. Gordon D'Arcy
23. Mick McGrath
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland