Cardiff Blues will be without Sam Warburton for their game against Ulster, while Rhys Patchell moves to full-back for the clash.
Cardiff Blues are missing Wales flank Sam Warburton for their game against Ulster, while Rhys Patchell moves to full-back for Friday's PRO12 fixture.
Josh Navidi has replaced Warburton in the side in what is an otherwise unchanged forward pack.
The backline however sees a few alterations as Patchell's move to number fifteen hands Gareth Davies a start at fly-half alongside Lewis Jones.
Gavin Evans and Adam Thomas, the latter in for Cory Allen, will be the centre combination while Richard Smith joins Alex Cuthbert on the wings.
“This game will give us another clear indication of exactly where we are as a group and, during what has been a quick turnaround between games, the squad has trained exceptionally hard as we look forward to getting back out on the field,” said the Blues director of rugby Mark Hammett.
“In the short period of time I've been at Cardiff Blues, it has been pleasing to see that we have assembled a group of players who are prepared to work hard and are eager to learn.
“We have had to deal with adversity for the first time this season over the last week, but have responded by showing the right attitude and resolve. Now we need to take that mentality and determination over the whitewash and into the Ulster game.
“We have made some changes to the team and look forward to seeing those combinations,” he added. “We have an agreement with the union over Sam Warburton's availability throughout the season and we have decided to make changes in the back row this week to ensure we get the very best out of him in the long-term while also giving players like Josh Navidi a deserved chance to impress.”
Meanwhile, British and Irish Lions winger, Tommy Bowe, and Ireland international fly-half, Paddy Jackson, will play their first match of the season on Friday.
They are two of five changes to the side that beat Zebre at Kingspan Stadium last weekend.
Louis Ludik, who started last week's game on the bench, is selected at full-back and is joined in the back three by two of the ten Ireland internationals in the side – Andrew Trimble, who starts on the right wing, and Bowe, who is named on the left.
Stuart Olding returns to the starting XV at inside centre, while Darren Cave has recovered from the rib injury that he sustained against Zebre to take his place at outside centre.
Jackson will play his 65th game for Ulster and is partnered by Paul Marshall at half-back.
Up front there is an unchanged front-row with Andrew Warwick and Wiehahn Herbst starting either side of captain, Rory Best.
Franco van der Merwe returns to the second-row and starts alongside Dan Tuohy while there is no change in the back-row where Robbie Diack, Chris Henry and Nick Williams all start.
Form: Cardiff Blues' solo victory in their last three Guinness PRO12 clashes was 41-26 against Zebre in Parma in round 1. The Blues have been victorious in their last two encounters with Irish provinces but have not won three in a row against opponents from that Union since May 2010. Ulster are unbeaten in the opening two rounds and have secured back-to-back try bonus points. The Ulstermen are winless against Welsh opposition since beating the Scarlets in Belfast in March, whilst their only victory in Wales since 2012 came at Ospreys last October. Each side won its respective home game during last season's PRO12 competition, whilst the Blues have not beaten Ulster in successive matches since April 2010. Ulster's only win at the BT Sports Cardiff Arms Park since September 2005 came on 28 September 2012, (although they did win when Cardiff moved home to the City Stadium).
Cardiff Blues: 15 Rhys Patchell, 14 Alex Cuthbert, 13 Adam Thomas, 12 Gavin Evans, 11 Richard Smith, 10 Gareth Davies, 9 Lewis Jones, 8 Manoa Vosawai, 7 Josh Navidi, 6 Josh Turnbull, 5 Filo Paulo, 4 Jarrad Hoeata, 3 Adam Jones, 2 Matthew Rees (c), 1 Sam Hobbs.
Replacements: 16 Rhys Williams, 17 Taufa'ao Filise, 18 Scott Andrews, 19 Macauley Cook, 20 Ellis Jenkins, 21 Lloyd Williams, 22 Cory Allen, 23 Geraint Walsh.
Ulster: 15 Louis Ludik, 14 Andrew Trimble, 13 Darren Cave, 12 Stuart Olding, 11 Tommy Bowe, 10 Paddy Jackson, 9 Paul Marshall, 8 Nick Williams, 7 Chris Henry, 6 Robbie Diack, 5 Franco van der Merwe, 4 Dan Tuohy, 3 Wiehahn Herbst, 2 Rory Best (c), 1 Andrew Warwick.
Replacements: 16 Rob Herring, 17 Callum Black, 18 Bronson Ross, 19 Neil McComb, 20 Roger Wilson, 21 Michael Heaney, 22 Ian Humphreys, 23 Craig Gilroy.
Date: Friday, September 19
Kick-off: 19:35 BST
Venue: BT Sports Cardiff Arms Park
Referee: Neil Paterson (SRU, 61st competition game)
Assistant Referees: Leighton Hodges, Jon Mason (both WRU)
Citing Commissioner: Denis Jones (WRU)
TMO: Gareth Simmonds (WRU)