The other changes to the starting line-up sees Dafydd Hewitt comes in at centre for Owen Williams, with Cory Allen moving to outside centre.
The pack remains the same and will again be captained by prop Gethin Jenkins in the front row. Taufa'ao Filise and Chris Czekaj return among the replacements.
Director of Rugby Phil Davies has called on his Blues to build on the region's Heineken Cup exploits, but acknowledged that Ulster will also be full of confidence after defeating Montpellier last week.
"We know what it is like to try and go to Montpellier and get a result so you have got to give them huge credit for that. It was a great performance by Ulster," said Davies.
"They are an outstanding team with some excellent players. They have got Johannn Muller who is a great catalyst for them with Nick Williams. You have John Afoa in the scrum with Rory Best so their platform is really good.
"You then have the half backs with Ruan Pienaar who navigates them around the field and Paddy Jackson is playing well. They have good finishing power on the wings with Andrew Trimble and Tommy Bowe. They are a very good team all-round.
"Ravenhill has been redeveloped and it will be a great atmosphere and a sell-out. It will be a great occasion and hopefully a great game."
Cardiff Blues: 15 Leigh Halfpenny, 14 Richard Smith, 13 Cory Allen, 12 Dafydd Hewitt, 11 Harry Robinson, 10 Rhys Patchell, 9 Lloyd Williams; 1 Gethin Jenkins (c), 2 Marc Breeze, 3 Scott Andrews, 4 Bradley Davies, 5 Filo Paulo, 6 Josh Navidi, 7 Sam Warburton, 8 Robin Copeland.
Replacements: 16 Kristian Dacey, 17 Sam Hobbs, 18 Taufa'ao Filise, 19 Lou Reed, 20 Rory Watts-Jones, 21 Lewis Jones, 22 Gareth Davies, 23 Chris Czekaj