Jamie Robinson has recovered from his ankle injury to take his place in the centre, Maama Molitika returns to the pack for his first start in nearly a month and Nick Macleoad starts at full back.
Xavier Rush will captain the side as Rhys Williams is still suffering form a hamstring injury but should return for the Leinster match.
Martyn Williams had a scan on his shoulder following the Connacht game and may take a place on the bench for the trip to Ulster.
This is must win match for both sides. Ulster are in second place in the table, with the Blues breathing down their necks in third.
Defeat for either side would seriously dent their title aspirations. But the Blues are on a six-match winning streak, and face league Leaders Leinster next weekend at the Millennium Stadium in what could be a championship decider.
15 Nick Macleod 14 Chris Czekaj 13 Jamie Robinson 12 Marc Stcherbina 11 Craig Morgan 10 Nick Robinson 9 Mike Phillips
8 Xavier Rush (c) 7 Robin Sowden-Taylor 6 Maama Molitika 5 Rob Sidoli 4 Deiniol Jones 3 Gethin Jenkins 2 T. Rhys Thomas 1 John Yapp
16 Ben Evans 17 Duane Goodfield 18 Kort Schubert 19 Mark Lewis / Martyn Williams20 Ryan Powell 21 Tristan Davies 22 Dafydd Hewitt