Jonathan Sexton returns to the Leinster line-up for the first time this season as the Boys in Blue take on Guinness PRO12 leaders Ospreys, on Friday. With Leinster having won two of their opening three league fixtures, losing only at Scotstoun, to Glasgow Warriors, head coach Leo Cullen welcomes Sexton back to the fray following the fly half’s shoulder surgery. And despite his talisman going under the knife this summer, Cullen is confident Sexton is fully fit and ready to do battle at the RDS Arena. “He’s trained well over the last number of weeks,” said Cullen. “He’s been fully involved in training. “Some injured players come back and they’re back on the field and they’re almost straight into it, whereas he’s managed himself – non-contact for a number of weeks. “He’s in a good place, training well. I’m looking forward to seeing him in action.” Ospreys head to the RDS on the back of three bonus-point wins, and Cullen is expecting a tough battle against the four-time Celtic League winners. “They’re very physical,” he added. “They’re a team that we have a lot of respect for because we’ve had some really good tussles with them over the years. “They’ve got a lot of international experience coming in. They’ve come out of the traps very quickly this year, they’ve got maximum points. “We know over the years the threats that they pose: some smart footballers, really good half-backs with international experience. “They’re very strong in the contact areas. It’s important that we are smart in the way we play because they’re a team that will put you under a lot of pressure.” While Leinster welcome Sexton back, Ospreys hand a first start of the season to their own superstar fly-half, Dan Biggar. The 26-year-old came on as a replacement in last week’s Round 3 win over Benetton Treviso, but the Wales international gets his first start while in-form Sam Davies moves to full-back. And whatever the result, there will be celebrations for the Wales region as Alun Wyn-Jones chalks up his 200thappearance for Ospreys. Head coach Steve Tandy, said: “There’s no bigger challenge in the Guinness PRO12 than going to the RDS to face a fully loaded Leinster team so we know we’re in for a tough evening. “We’ve made a positive start to the season but we know it doesn’t count for anything at this point. We have to go up a few levels now with Ulster away and then the Blues at the Liberty coming up after this weekend. “We’ll definitely have a better grasp of where we are at in a few weeks time. “What’s been particularly pleasing over the last few weeks has been how the players have transferred what they’ve been working on during the week into the 80 minutes on matchday. “They know what is required of them, what they are expected to do, and they’ve been relentless in each of the three games so far. The attention to detail has largely been there and that’s reflected on the scoreboard.” Leinster: Kirchner, Nacewa, Ringrose, Reid, Kearney D, Sexton, McGrath L, Healy, Cronin, Furling, Toner, Kearney M, Murphy, van der Flier, Heaslip Replacements: Tracy, McGrath J, Ross, Molony, Ruddock, Leavy, Gibson-Park, Carbery Ospreys: Davies, Hassler, Beck, Matavesi, John, Biggar, Webb, James, Baldwin, Arhip, Ashley, Jones, King, Tipuric, Ardron Replacements: Parry, Smith, Fia, Davies, Baker, Habberfield, Howells, Evans Overall Guinness PRO12 head to head record: Played 28, Leinster won 14, Ospreys won 11 and 3 games drawn At RDS Arena, 7:35pm. Live on TG4 and BBC Wales Referee: Marius Mitrea (FIR, 55th competition game) Assistant Referees: Matteo Liperini (FIR), Stuart Gaffikin (IRFU) Citing Commissioner: Eugene Ryan (IRFU) TMO: Carlo Damasco (FIR)