Williams' has named an unchanged pack for the Cardiff game, from last week's starting XV, who gained victory over Glasgow at Firhill. One change has been made in the backs, with Ulster centre Darren Cave starting at No.13, while academy player Ian Whitten takes to the bench, for the start of Ulster's final Magners League home game of the season.
In the replacements; Ulster development player Daniel Roach has been replaced with the experienced Ulster and Irish prop Tom Court.
Ulster Team
(1-8) Bryan Young, Rory Best (Capt), Brendon Botha, Carlo Del Fava, Ryan Caldwell, Stephen Ferris, David Pollock, Robbie Diack.
(15-9) Clinton Schifcofske, Simon Danielli, Darren Cave, Paddy Wallace, Andrew Trimble, Niall O'Connor, Paul Marshall.
Ulster Replacements
(16-22) Nigel Brady, Tom Court, Matt McCullough, Chris Henry, Isaac Boss, Ian Whitten, Ian Humphreys
Tickets are still available for the Ulster v Cardiff Magners League fixture from www.ulterrugby.com and the Ulster Rugby ticket office. Tickets will also be available to purchase on match night before the game.
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland