Boss links up with Ian Madigan at half-back in a back-line which also includes Luke Fitzgerald. In addition, Eoin O'Malley makes his return from injury and lines up alongside Eamonn Sheridan at centre.
Andrew Conway, who was a replacement in Leinster's victory over the Melbourne Rebels last weekend, starts at full-back with Fionn Carr completing the back-three.
Young back rower Rhys Ruddock leads the province's selected side which includes two debutants in the pack - Ireland hooker Cronin and former Northampton lock Damian Browne.
Tickets will be available on the gate from 10 euro (adult) and 5 euro (child), while stand tickets cost 20 euro (adult) and 10 euro (child).
Tickets are also available to buy online here, from the Leinster Rugby Store (Donnybrook), Spar (Donnybrook) and from Ticketmaster outlets nationwide.
LEINSTER (v Northampton Saints): Andrew Conway; Fionn Carr, Eoin O'Malley, Eamonn Sheridan, Luke Fitzgerald; Ian Madigan, Isaac Boss; Heinke van der Merwe, Sean Cronin, Jamie Hagan, Damian Browne, Steven Sykes, Kevin McLaughlin, Dominic Ryan, Rhys Ruddock (capt).
Replacements: Aaron Dundon, Jack McGrath/Simon Shawe, Jack O'Connell, Devin Toner, Shane Jennings, John Cooney/Cillian Willis, Mat Berquist, Brendan Macken, Jason Harris-Wright, Mark Flanagan, Leo Auva'a, Darren Hudson.