Cathal Marsh will captain Leinster 'A' in a half-back pairing with Charlie Rock who comes in to start against Cardiff having appeared from the bench in the last round against Bristol. The only other back-line change from that game sees Jack Kelly named on the right wing in place of Hugo Keenan who is in South America with the Ireland Sevens squad.
There is an all-new front row for Saturday's round 5 game in Wales with Peter Dooley, Ronan Kelleher and Jack Aungier all selected to start. Mick Kearney comes in to partner Ian Nagle in the second row.
Max Kearney, who captained Belvedere College to their second successive Leinster Schools Senior Cup title last March, is named in the back row with the senior-capped Josh Murphy and Peadar Timmins.
Speaking to leinsterrugby.ie ahead of this weekend's match, Leinster 'A' head coach McNamara said: "We've put ourselves in a strong position - the four wins from four has been great. It's important now in these next two games that we get results to give us the best possible opportunity to advance in the competition.
"It's an opportunity this week for a couple of younger guys. Max Kearney is making his debut, but also Jack Aungier and Ronan Kelleher are making their first starts. The Cardiff team is experienced, they've got Welsh internationals involved, so it's going to be a big test."
Leinster 'A' return to Donnybrook on Saturday week (January 20) to play Doncaster in a game that could determine who tops the pool and progresses to the quarter-finals with home advantage. Tickets can be purchased online from Ticketmaster from €10/5 or supporters can pay cash on the gate. Season Ticket holders can enter for free when they show their 2017/18 Season Ticket card at the gate.
LEINSTER 'A' (v Cardiff Blues Premiership Select): Ciaran Frawley; Jack Kelly, Gavin Mullin, Conor O'Brien, Tommy O'Brien; Cathal Marsh (capt), Charlie Rock; Peter Dooley, Ronan Kelleher, Jack Aungier, Mick Kearney, Ian Nagle, Josh Murphy, Max Kearney, Peadar Timmins.
Replacements: Sean McNulty, Adam Coyle, Oisin Heffernan, Oisin Dowling, Ronan Foley, Hugh O'Sullivan, Michael Silvester.