Leinster coach Matt O’Connor has made four changes to his starting XV for Saturday night’s return fixture against Harlequins at the Aviva Stadium (7.45pm).

As expected, Luke Fitzgerald moves from the left wing to outside centre in place of the injured Gordon D'Arcy, with Darragh Fanning switching from the right to left wings and Zane Kirchner coming in on the right.

The other change in the backs sees Isaac Boss edges out Eoin Reddan at scrumhalf, with Reddan moving to the bench.

There are two changes in the pack with Kane Douglas replacing Mike McCarthy in the secondrow and Dominic Ryan starting at openside flanker after recovering from a quad muscle strain.

Harlequins have confirmed that England captain Chris Robshaw has been ruled out for up to four weeks with the shoulder injury he sustained in last week’s win over Leinster at The Stoop .

“Following consultation with a specialist, the Rugby Football Union and the Harlequins medical team, Robshaw is expected to return in three to four weeks”, read a statement released by Harlequins.

Robshaw completed the win against Leinster despite suffering the ‘stinger’ to his shoulder and while surgery is not required, he is set to miss up to four matches.

His place goes to former England under-20 flanker Jack Clifford, with the other change to the Harlequins starting XV also forced by an injury, as South African Tim Swiel takes over from Nick Evans at outhalf having replaced him after 12 minutes of last weekend’s game after he picked up a shoulder injury.

Luke Marshall has recovered from injury and has been named in the Ulster starting XV to face Scarlets at Parc y Scarlets on Sunday (5.15pm).

The Ireland international centre suffered a knee injury while playing for the Ravens in October and returns to the side at inside centre.

Marshall’s inclusion is one of three personnel changes and one positional switch to the side that recorded a bonus-point win over the same opposition at Kingspan Stadium last weekend.

Nick Williams and Wiehahn Herbst miss the game with hamstring injuries so Roger Wilson moves to number eight, Clive Ross is named at openside, with Ireland international Declan Fitzpatrick selected at tighthead prop.

Stuart Olding also misses the game having suffered concussion in last Saturday’s match.

Ruan Pienaar continues at scrumhalf alongside Ian Humphreys, Marshall partners last weekend’s man of the match Darren Cave in midfield with Louis Ludik at fullback and Ireland internationals Tommy Bowe and Craig Gilroy selected in the back three.

Captain Rory Best is joined by Callum Black and Fitzpatrick in the frontrow, while Franco van der Merwe has recovered from the head injury he suffered last weekend and is selected in the second row along with Ireland international secondrow Dan Tuohy.

Clive Ross and Wilson start alongside Robbie Diack in the backrow.

Prop Bronson Ross is named among the substitutes and is in line to make his first appearance in the competition.

LEINSTER (v Harlequins, Aviva Stadium, Saturday, 7.45pm): Rob Kearney; Zane Kirchner, Luke Fitzgerald, Ian Madigan, Darragh Fanning; Jimmy Gopperth, Isaac Boss; Jack McGrath, Seán Cronin, Mike Ross; Devin Toner, Kane Douglas; Rhys Ruddock, Dominic Ryan, Jamie Heaslip (capt).

Replacements: Bryan Byrne, Michael Bent, Tadhg Furlong, Mike McCarthy, Jack Conan, Eoin Reddan, Noel Reid, Mick McGrath.

HARLEQUINS: Mike Brown; Marland Yarde, Matt Hopper, George Lowe, Aseli Tikoirotuma; Tim Swiel, Danny Care; Joe Marler (capt), Dave Ward, Will Collier; Charlie Matthews, George Robson; Luke Wallace, Jack Clifford, Nick Easter.

Replacements: Joe Gray, Mark Lambert, Kyle Sinckler, Sam Twomey, Joe Trayfoot, Karl Dickson, Tom Casson, Ross Chisholm.

ULSTER (v Scarlets, Parc y Scarlets, Sunday, 5.15pm): Louis Ludik; Tommy Bowe, Darren Cave, Luke Marshall, Craig Gilroy; Ian Humphreys, Ruan Pienaar; Callum Black, Rory Best (capt), Declan Fitzpatrick; Dan Tuohy, Franco van der Merwe; Robbie Diack, Clive Ross, Roger Wilson.

Replacements: Rob Herring, Andrew Warwick, Bronson Ross, Alan O'Connor, Mike McComish, Paul Marshall, Michael Heaney, Mike Allen.

SCARLETS: Liam Williams; Kristian Phillips, Regan King, Scott Williams (capt), Michael Tagicakibau; Rhys Priestland, Rhodri Williams; Rob Evans, Emyr Phillips, Samson Lee; Jake Ball, Johan Snyman; Aaron Shingler, James Davies, Rob McCusker.

Replacements: Kirby Myhill, Wyn Jones, Rhodri Jones, George Earle, Rory Pitman, Aled Davies, Steven Shingler, Hadleigh Parkes.