The Ospreys will be looking to bounce back from their 17-0 loss to Gloucester in the EDF Energy Cup by getting back on track in the Magners League at Ulster, but will be without a number of internationals.
The region were hit by a double blow this week, with Wales pair Gavin Henson and Jonathan Thomas being ruled out for the rest of the season.
Flanker Thomas has suffered a recurrence of a long-term groin problem, and has been advised to take three months recovery, while centre Henson was withdrawn during Saturday's semi-final against Gloucester and will out until early May.
Ian Gough was also taken off against Gloucester, suffering a haematoma in his hip, and will miss the Ulster clash but hopes to be fit for next weekend's match with Munster in the Heineken Cup quarter-final.
Lee Byrne remains on the sidelines as he recovers from damaged ligaments suffered in Wales's Six Nations finale against Ireland, while two other Welsh internationals in Shane Williams and captain Ryan Jones will not travel with the side to Northern Ireland.
Host Ulster had found form during the Six Nations break, having won both of their matches in this period, although like the Ospreys lost to Leinster in their last Magners League game.
Coach Matt Williams will be without Stephen Ferris, Bryn Cunningham and Paul Steinmetz but can call upon NiallO'Connor and Mark McCrea, who have been added to the squad for Friday night. And Williams is taking nothing for granted despite the Welsh region's weakened state.
"The Ospreys are a fantastic team and physically massive. No-one expects us to win so there isn't much pressure on us," said Williams.
"They are individually the best team in the competition with a big squad of very high quality players so it could be our toughest game at Ravenhill this season."
Forwards: Brendon Botha, Tom Court, Bryan Young, Ed O'Donoghue, Matt McCullough, Carlo del Fava, Chris Henry, Nigel Brady, David Pollock, Rory Best, Ryan Caldwell, Robbie Diack.
Backs: Simon Danielli, Andrew Trimble, Darren Cave, Cillian Willis, Niall O'Connor, Clinton Schifcofske, Ian Whitten, Isaac Boss, Ian Humphreys, Timoci Nagusa, Mark McCrea, Paddy Wallace.
Ospreys : Gareth Owen; David Bishop, Jonathan Spratt, Andrew Bishop, Jonny Vaughton; James Hook, Mike Phillips; Paul James (capt), Huw Bennett, Cai Griffiths, Alun Wyn Jones, Andy Lloyd, Tom Smith, Steve Tandy, Filo Tiatia.
Replacements: Richard Hibbard, Ryan Bevington, Filipo Levi, Marty Holah, Jamie Nutbrown, Dan Biggar, Sonny Parker.
Angus O'Brien has quickly settled into the Wales Sevens squad after solid performances in Hong Kong and Japan. With two rounds remaining in Glasgow and Twickenham on the World Series, WRU TV's Graeme Gillespie chats to the rising star.
Wales winger Luke Morgan has established himself as one of the deadliest finishers on the Sevens World Series. WRU TV's Graeme Gillespie catches up with him on the eve of this weekend's round in Glasgow.
All roads lead to Cardiff on Sunday for the SSE SWALEC Finals Day at the Millennium Stadium. Cambrian Welfare tackle Ystradgynlais in the Bowl final, Ystrad Rhondda play Newcastle Emlyn in the Plate final while defending champions Pontypridd face Bridgend in the Cup final.
WRU Chief Executive Roger Lewis, Deputy Minister for Culture, Sport and Tourism Ken Skates and WRU Chairman Gareth Davies earlier this week launched a new competition in conjunction with the WRU unveiling its archive room.
Welsh players and management joined Deputy Minister for Sport Ken Skates at the Pierhead Building, Cardiff Bay earlier this week to reveal the Union's pioneering school-club hub initiative has been so successful the project will now almost double the scale of the original project.
The Scarlets, Newport Gwent Dragons, Cardiff Blues and the Ospreys look ahead to Judgement Day III which sees the Blues take on the Ospreys (2.30) and the Dragons tackle the Scarlets (4.45pm) at the Millennium Stadium tomorrow afternoon.
Ystradgynlais and Ynysddu played out a titanic struggle at Taffs Well in the SSE SWALEC Bowl semi-final. At the end of the game neither team could be separated after a 15-15 stalemate but Ystradgynlais go through on try count.
Blues strike first in JD III battle - Newport Gwent Dragons lock Andrew Coombs, WRU referee Dylan Llyr Jones and Cardiff Blues hooker Matthew Rees decide dressing room allocations for Judgement Day III
Wales Under 18 captain Calum Haggett has received a conditional offer to read Biomedical Science at St Anne's College, Oxford. WRU chairman Gareth Davies went to meet Calum and Coleg y Cymoedd Principal Judith Evans to wish him luck in his exams and pass on some of his personal experience.