Ian Humphreys and BJ Botha return to the preliminary squad which will face their Welsh play-off rivals. Botha has not played since injuring his elbow before Christmas while Humphreys pulled a hamstring during training in February. The return of both players will be a timely boost for Ulster with a string of important matches coming up.

Captain Rory Best is back in contention for a starting place after coming on after 50 minutes last week against Glasgow. Conor Gaston is named in the preliminary squad for the third week running after impressive performances in his first two appearences.

Ulster currently sit third in the Magners League after a run of five straight wins and will be hoping to continue their rise up the table. With a Heineken Cup Quarter Final against Northampton just 9 days after Scarlets, McLaughlin will be hoping for an improved performance after scraping past Aironi and Dragons in their last two outings.

The Scarlets occupy 6th position but are just 5 points adrift of Ulster and with a Magners League semi-final spot up for grabs, it promises to be a tense game.

ULSTER SQUAD FORWARDS
Jerry Cronin, Declan Fitzpatrick, Tom Court, BJ Botha, Paddy McAllister, Bryan Young, Rory Best, Nigel Brady, Andi Kyriacou, Ryan Caldwell, Dan Tuohy, Johann Muller, Tim Barker, Pedrie Wannenburg, TJ Anderson, Willie Faloon, Chris Henry, Robbie Diack.

ULSTER SQUAD BACKS
Ruan Pienaar, Paul Marshall, Ian Humphreys, Niall O'Connor, Ian Whitten, Nevin Spence, Paddy Wallace, Darren Cave, Mark McCrea, Andrew Trimble, Simon Danielli, Tommy Seymour, Craig Gilroy, Conor Gaston, David McIlwaine, Jamie Smith, Adam D'Arcy.