Gordon D'Arcy is one of nine full Ireland internationals in all and he joins Isa Nacewa, a try scorer last weekend, and man of the match Sean O'Brien in the squad which is expected to be reduced on Thursday lunchtime.
Leinster defence coach Kurt McQuilkin said the squad still have areas that need improving against a strong Ospreys side.
"Friday's game presents a real challenge to us. It was good to get our first win of the campaign last weekend, but even in victory there were areas that we need to improve. Defensively we weren't happy with our first-up tackling or our line speed. Our resets worked well but we have work to do this week.
"I think that the first two games of the season have shown that there's good competition for places in our squad. The depth in all positions means that players know that if they slip up in training or in matches that there will be someone chomping at the bit to get into each week's team. If you have an average day at the office then you could lose your place and I think that that fear drives the players on.
"It was good for the likes of Darce (Gordon D'Arcy), Nathan (Hines) and Redser (Eoin Reddan) to get their first game of the season under their belts so they, along with the other returning players, will get sharper as the games come on thick and fast. Mike Ross performed strongly up front along with the other forwards so our form is improving.
"There was no resting on our laurels over the summer and though last year went well, with the way teams scout each other nowadays you can't sit back on past success. We've got to continue to hammer home the basics and keep adding things to your armoury. Something that I've been really impressed with over the last few months is the positive approach that the players have made in training. Their heads are screwed on and they're striving to improve, demanding more and more of the coaches and of themselves which is helping to build a strong culture.
"The Ospreys are an outstanding with speed, power and skill across their pack and backline. In (Jerry) Collins, (Filo) Tiatia and Ryan Jones they have a really physical back-row presence who will come right up at you in midfield. Then take someone like Mike Phillips who is a key man for them. He likes to probe around the fringes and is another big presence and with players of the calibre of Jonny Vaughton, Tommy Bowe and Shane Williams out wide they have serious pace which we will need to contend with.
"Even though they will have been disappointed with their defeat to Ulster last time out, they remain serious contenders for the title and we know that we will need to raise our performance levels to get a result. It just shows how wide open the competition is this year."
Leinster squad to face the Ospreys
BACKS: Shaun Berne, Gordon D'Arcy, Girvan Dempsey, Shane Horgan, Chris Keane, David Kearney, Simon Keogh, Fergus McFadden, Isa Nacewa, Paul O'Donohoe, Eoin Reddan, Jonathan Sexton
FORWARDS: Leo Cullen, John Fogarty, Jason Harris-Wright, Cian Healy, Nathan Hines, Bernard Jackman, Shane Jennings, Stephen Keogh, Ronan McCormack, Kevin McLaughlin, Sean O'Brien, Malcolm O'Kelly, Mike Ross, Devin Toner, Stan Wright