Trimble takes up the right wing position with Craig Gilroy switching to the left and Simon Danielli dropping to the bench. Prop Tom Court takes the place of Bryan Young who will also start from the bench. Paddy Wallace joins the in-form Nevin Spence in the centre, so Ian Whitten drops out of the match day squad.
The other notable inclusions are TJ Anderson in the back row in place of Willie Faloon and Andi Kyriacou at hooker instead of Nigel Brady. Johann Muller will again captain the side in the continued absence of Rory Best, who is still on Ireland duty along with Stephen Ferris.
Ulster A D'Arcy; A Trimble, N Spence, P Wallace, C Gilroy; I Humphreys, R Pienaar: Tom Court, A Kyriacou, D Fitzpatrick, J Muller, T Barker, TJ Anderson, C Henry, P Wannenburg;
Replacements: N Brady, J Cronin, B Young, R Caldwell, R Diack, P Marshall, L Marshall, S Danielli.