18 May, 11:09
IRFU Chief Executive Philip Browne has issued a statement following confirmation of Ronan O'Gara's decision to retire from playing professional rugby.
Both Best and Wallace are returning from international duty after coming on as second half replacements in Ireland's 34-13 Six Nations win over Scotland last Saturday.
Commenting on the Scarlets game, Best said: "We want to built on our performance against the Dragons. It was a much-needed win but there are still aspects that we want to improve and are working on. We are never going to get carried away - we have got a lot of work to do before the end of the season.
"I'm really looking forward to getting back out at Ravenhill with Ulster. It's always good to come back after the onternationals and settle back in with the faces that you train with every day. The whole squad is working extremely hard for the match ahead and I'm glad that I can come back to be a part of that."
In the backs, Bartholomeusz starts at full-back with Bryn Cunningham dropping to the bench and Mark McCrea and Simon Danielli keeping hold of the wing spots.
Wallace starts at centre alongside Paul Steinmetz with Ireland 'A' international Darren Cave named as cover on the bench. Isaac Boss retains the number 9 jersey and will play alongside Limavady man Niall O'Connor at half-back.
Returning to the starting line-up in the forwards is Matt McCullough, who recently captain Ulster 'A' and has edged out Neil Best for the number 6 jersey.
Ryan Caldwell and Justin Harrison are named as the second row options with Italian lock Carlo Del Fava, who has escaped a ban after his incident with Wales' Stephen Jones at the weekend, covering on the bench. In the front row the Australia-born Court is named at tighthead with Bryan Young on the loosehead side of the scrum.
The man-of-the-match in Ulster's 38-13 triumph over the Dragons, Stephen Ferris will start tomorrow night at number 8 and is determined to get a long-awaited win over the Scarlets.
"I have only beaten Llanelli Scarlets once, at Ravenhill two years ago. So I really want to get one over on them again. In my first season we went over there and drew 12-12 which was a great result as we ended up winning the Magners League," said the Ireland back rower.
"But since then we haven't been doing too well and I think we have to step up another level and get stuck into them. I would take a one-point win now. It is so vital for us to get another victory and get the crowd behind us."
Promenade and Terrace tickets are still available for the game. Tickets can be purchased from Ravenhill or from the Ulster Rugby ticket line on 028 9049 3222 (select option 2) or online at the Ulster Rugby website anytime.
Tickets can also be bought from various ticket outlet shops across the province, including: In Sport - Newtownards, SS Moore's - Belfast, Athletic Stores - Belfast, Eden Park - Belfast, Euro Sport - Lisburn, Shoe Fair Sports - Banbridge, Style N Sport - Ballymena, Vi-Sport - Belfast, David Gotto All Sports - Belfast, Overplay Sports - Carrickfergus and Douglas & Grahame Ltd - Belfast.
ULSTER (v Llanelli Scarlets): Mark Bartholomeusz; Simon Danielli, Paul Steinmetz, Paul Wallace, Mark McCrea; Niall O'Connor, Isaac Boss; Bryan Young, Rory Best (capt), Tom Court, Justin Harrison, Ryan Caldwell, Matt McCullough, Kieron Dawson, Stephen Ferris.
Replacements: Nigel Brady, Justin Fitzpatrick, Carlo Del Fava, Neil Best, Paul Marshall, Darren Cave, Bryn Cunningham.