There are competitive debuts for the half-back pairing of John Cooney and Mat Berquist, while second row Damian Browne also comes in for his first start.
Browne will link up with Ireland international Devin Toner, and Heinke van der Merwe has been named in the front row alongside Richardt Strauss and recent signing Jamie Hagan.
There are six recent Leinster Academy graduates on the replacements bench. Amongst them is scrum half Cillian Willis, who rejoined the province this summer having made the last of his 12 appearances in the 2007/08 season.
LEINSTER (v Ospreys): Isa Nacewa; Fionn Carr, Eoin O'Malley, Luke Fitzgerald, David Kearney; Mat Berquist, John Cooney; Heinke van der Merwe, Richardt Strauss, Jamie Hagan, Damian Browne, Devin Toner, Kevin McLaughlin, Dominic Ryan, Rhys Ruddock (capt).
Replacements: Aaron Dundon, Jack McGrath, Jack O'Connell, Mark Flanagan, Leo Auva'a, Cillian Willis, Ian Madigan, Brendan Macken.