With nine players away on international duty, Ospreys head coach Steve Tandy has rung the changes for the clash with the Heineken Cup champions.
Matthew Dwyer makes his debut at hooker while Lloyd Peers makes his first RaboDirect PRO12 start in the second row.
Arthur Ellis, Marc Thomas and Daniel Suter will all make their Ospreys debuts if they come off the bench.
Ian Gough may be available next week but misses out against Leinster after undergoing treatment for an ongoing medical problem.
With a number of new faces in the squad, Rees is hoping some of the region’s younger players can step up to cover for the likes of Dan Biggar, Ryan Jones and Alun Wyn Jones.
“November is going to be a big month for us, as is always the case,” said Rees.
“With international players away, it’s always a challenge and a great opportunity for some of our younger players to stand up and show what they are capable of.
“As someone who has done a lot of work with the younger players, I’m looking forward to the games this month. With two LV= Cup games to follow then two more PRO12 matches, it’s a crucial time of the season and it’s important that the work we’ve done in preparing for this period bears fruit.”
Last year’s PRO12 champions had a poor start to their campaign this year, losing their first three fixtures but have bounced back and sit in sixth place, two behind Leinster.
The likes of Justin Tipuric and Ashley Beck have impressed in the past after being given the chance to impress for their region during international periods and Rees is hoping for something similar this year.
“Last season’s title success was driven by the core group of players who were around in the international periods, who got that great six game winning start to the season to put us in a great position, beat a full strength Munster in November and kept things going in February,” he added.
“It’s a great opportunity for guys coming in to show they are good enough to be at the Ospreys. It’s at times like this that players such as Justin Tipuric, Ryan Bevington and Ashley Beck have excelled in recent seasons and they’ve used it to kick on and establish themselves with both their region and their country.
“We’ll be expecting some of the players involved this month to have a similar impact so it’s exciting for coaches and players and I’d expect our supporters to feel the same.”
After inflicting a heavy defeat on the Blues in Dublin last week, Leinster will be full of confidence though they too make a number of changes.
Andrew Goodman makes his debut at inside centre while David Kearney is one of only two players who retain their place from last week’s win. He moves to full-back with Andrew Conway and Fionn Carr named on the wings.
Irish scrum-half Isaac Boss partners Ian Madigan at half back while Shane Jennings leads the team and is named in the back-row alongside No. 8 Leo Auva’a and Rhys Ruddock.
“We know that Leinster may have an unfamiliar look to their team this weekend but we also know that as European champions they have real strength in depth and whatever players wear their shirt we will be in for a real test,” added Rees.
“As with any match, our preparation is all about focusing on our own game and ensuring that we are ready, are precise and accurate in what we do.
“We know that if we get that right, we should get the kind of performance we want.”
