Scotland's Hines partners Malcolm O'Kelly in the second row, while in the front row Stan Wright lines up alongside Cian Healy and John Fogarty.
Ireland scrum half Reddan will link up with Jonathan Sexton in a back-line which also sees Gordon D'Arcy come in for his first start of the season.
The back-three of David Kearney, Shane Horgan and Isa Nacewa remains the same as the one that started last weekend's 23-14 victory over the Dragons at the RDS.
The replacements bench will be confirmed closer to kick-off.
Looking to build on that first win of the campaign over the Dragons, full-back Nacewa is expecting a fiercely competitive game against the Ospreys.
"The Ospreys will prove to be a stiff test for us coming, as it does, after having lost their last game at home to Ulster," he said.
"Like us, they have a proud record at home and I'm sure that they'll be determined to get back to winning ways so we'll need to be focused and wary of them.
"I'm definitely pleased with our form after the first two games. As a squad we felt that had we been a bit more clinical against the Scarlets in week one then we could have won that game and though the Dragons were tough opponents, we showed definite improvements last weekend in the RDS.
"We've seen a fair bit of the Ospreys in recent weeks and they're an extremely talented side.
"Friday's game will have a Super 14 feel to it with Jerry Collins, Filo Tiatia and Marty Holah. They're three top class performers and I've played against them back in New Zealand.
"It will be a real battle up front to match them, but we know that the Ospreys have a lot of other threats."
The Aucklander added: "There was a bit of talk about the challenges facing us with three of the first four games being away from home, but we know the confidence that breeds from winning on the road.
"It helps morale, sets you up for the challenges ahead and, most importantly, it gets you up the Magners League table.
"Friday night will be a tough task for us, but it's one that we are going to have to meet head on."
LEINSTER (v Ospreys): Isa Nacewa; Shane Horgan, Gordon D'Arcy, Shaun Berne, David Kearney; Jonathan Sexton, Eoin Reddan; Cian Healy, John Fogarty, Stan Wright, Nathan Hines, Malcolm O'Kelly, Kevin McLaughlin, Shane Jennings (capt), Sean O'Brien.
Replacements (from): Bernard Jackman, Mike Ross, Leo Cullen, Devin Toner, Stephen Keogh, Chris Keane, Fergus McFadden, Simon Keogh.