Earls was a late withdrawal from the team to face the Dragons, pulling out with a stomach bug, and Flannery and Dowling proved their fitness with run-outs last week for Shannon and Munster 'A' respectively.
Munster coach Tony McGahan met with the media on Wednesday after the squad training session in the University of Limerick, and he knows more than anybody what 'a tough challenge Munster face this weekend.'
"We need to be a lot better than last week going into this game and we need to build on each game gradually," he said.
"As ever this is a local derby and the stakes are always very high, but we look forward to the clash and what Leinster represents."
Looking ahead to the next two weekends - including his side's European opener away to Northampton Saints - McGahan commented: "Of course both the games will bring their own challenges but all we need to do is make sure we perform better than last week."
Speaking about last season's Heineken Cup semi-final loss to Leinster, team captain Paul O'Connell said: "Coming up against them, yeah it's always in the back of the mind but we want to really focus on ourselves more than the past, Leinster and the hype of the game.
"We have to look after ourselves and not worry about Leinster.
"For me this is my first game back and the likes of Donners (Donncha O'Callaghan) and ROG (Ronan O'Gara) were involved last week and they'll no doubt be looking to build on that."
MUNSTER Squad (v Leinster): Backs (12) - Tomas O'Leary, Toby Morland, Peter Stringer, Ronan O'Gara, Paul Warwick, Jean de Villiers, Lifeimi Mafi, Doug Howlett, Ian Dowling, Denis Hurley, Keith Earls, Felix Jones.
Forwards (14) - Marcus Horan, John Hayes, Tony Buckley, Denis Fogarty, Jerry Flannery, Donncha O'Callaghan, Mick O'Driscoll, Paul O'Connell, Donnacha Ryan, Denis Leamy, Niall Ronan, David Wallace, Nick Williams, Alan Quinlan.