ULSTER (1st) v OSPREYS (4th), Ravenhill, 7.05pm (live BBC 2 Northern Ireland/BBC 2 Wales)
Team News: Ireland Under-20 international Stuart Olding will make his first start for Ulster against the Ospreys at a sold-out Ravenhill on Friday night.
Olding, a Hughes Insurance Ulster Academy graduate, has made three previous appearances, all as a replacement for the RaboDirect PRO12 leaders.
Johann Muller has returned from injury to captain the side, as has Luke Marshall who will line out in the unfamiliar outside centre position.
Ballymena prop Andrew Warwick is in line to make his senior debut for the province after being named on the replacements bench.
Callum Black will start at loosehead prop so Tom Court moves to the other side of the front row with Rob Herring slotting in at hooker.
Lewis Stevenson retains his place in the second row beside Muller, despite the return to action of Dan Tuohy who is listed among the replacements.
Mike McComish and Ali Birch get opportunities in the back row alongside the dynamic Robbie Diack.
The 19-year-old Olding will be surrounded by experience in the form of Ruan Pienaar at scrum half) and inside centre Paddy Wallace. Outside Marshall will be Andrew Trimble and Michael Allen on the wings, with Ricky Andrew positioned at full-back.
The province's bench features the 21-year-old Warwick and Belfast Harlequins duo Niall Annett and Ricky Lutton as the front row cover.
Tuohy and Neil McComb will offer plenty of options, particularly in the lineout, if they are called upon, while Paul Marshall, Darren Cave and Chris Cochrane are the replacement backs.
Meanwhile, the Ospreys will field a young and inexperienced team in Belfast due to injuries and international call-ups.
Steve Tandy's men travel across without their Wales senior, Under-20 and Sevens internationals - 16 players in all - and Andrew Bishop (back), Rhys Webb (concussion), Ashley Beck (ankle) and Tom Smith (groin) are among their injured players.
Ben John will make his league debut on the left wing with fellow winger Tom Habberfield and flanker Tom Habberfield set for their first starts in the RaboDirect PRO12.
There are two more potential league debutants on the replacements bench in Arthur Ellis and Jamie Murphy.
The Welsh region are fourth in the table after edging out bottom side 16-15 in their last league fixture in January. Out-half Dan Biggar was their saviour that night in Swansea scoring a try, a conversion and three penalties.
ULSTER: Ricky Andrew, Andrew Trimble, Luke Marshall, Paddy Wallace, Michael Allen; Stuart Olding, Ruan Pienaar; Callum Black, Rob Herring, Tom Court, Johann Muller (capt), Lewis Stevenson, Mike McComish, Ali Birch, Robbie Diack.
Replacements: Niall Annett, Ricky Lutton, Andrew Warwick, Dan Tuohy, Neil McComb, Paul Marshall, Darren Cave, Chris Cochrane.
OSPREYS: Richard Fussell; Tom Habberfield, Tom Isaacs, Jonathan Spratt, Ben John; Matthew Morgan, Kahn Fotuali'i (capt); Ryan Bevington, Scott Baldwin, Cai Griffiths, Ian Gough, James King, Morgan Allen, Sam Lewis, Joe Bearman.
Replacements: Matthew Dwyer, Duncan Jones, Dmitri Arhip, Alun Wyn Jones, Lloyd Peers, Arthur Ellis, Ross Jones, Jamie Murphy.
Referee: Marius Mitrea (Italy)
Assistant Referees: Paul Haycock, Nigel Correll (both Ireland)
Television Match Official: Simon McDowell (Ireland)
Match Odds (Paddy Power): Ulster to win: 2/9; Draw: 25/1; Ospreys to win: 10/3
Pre-Match Quotes: Robbie Diack (Ulster) - "It's really good that we've got Johann (Muller) back as he is world class at calling lineouts and I think it's good that I can now focus solely on my game and get back into carrying and getting in some good hits," he told the Belfast Telegraph.
"I was calling the lineouts (against Castres Olympique) and they didn't go too well in the first half and though the wind didn't help we had a few missed balls and miscommunications.
"It was good to get a few carries but it wasn't the best game of rugby. But to get a win (in France) was something that made us really happy.
"It's been about being given opportunities and taking them. With Mark (Anscombe), if you're not playing well then you have to be prepared to go and sort your game out, but in saying that if you are playing well he keeps you in the team."
Steve Tandy (Ospreys) - "We've got a very big month ahead of us, with three very difficult away games in Ireland and a home game against Edinburgh in a couple of weeks.
"It's going to be a season defining period for us. We've bounced back well from the slow start we had to the season and when the PRO12 broke up at the start of last month we had managed to claw our way up into the top four. The challenge now is to stay there, and it won't be easy.
"It's a really challenging period for the organisation. With more than 20 players missing this weekend we are pretty stretched, particularly when you look at the squad Ulster have with real world class quality in the group that is available to them all season long.
"It's the reality of our current situation that we are going to Ravenhill with a young looking group and a few boys making PRO12 debuts, but we know that we have a tight knit squad of players who believe in the cause and will play with real pride in the jersey."
Top Scorers - 2012/13 RaboDirect PRO12: Ulster - Points: Paddy Jackson 67; Tries: Nick Williams 6; Ospreys - Points: Dan Biggar 103; Tries: Richard Fussell 3
RECENT LEAGUE MEETINGS:
Tuesday, April 13, 2010 - Ulster 27 Ospreys 38, Ravenhill
Friday, September 3, 2010 - Ulster 27 Ospreys 26, Ravenhill
Sunday, February 13, 2011 - Ospreys 23 Ulster 22, Liberty Stadium
Sunday, September 25, 2011 - Ospreys 32 Ulster 14, Liberty Stadium
Friday, February 24, 2012 - Ulster 15 Ospreys 14, Ravenhill
Saturday, September 8, 2012 - Ospreys 13 Ulster 16, Liberty Stadium
- Ulster's only defeat in the first 13 rounds of the RaboDirect PRO12 was 24-10 to Munster at Thomond Park on December 29
- The Ulstermen's only reversal at Ravenhill in the league since October 2011 was 16-8 to Leinster on April 20 last
- Ulster have won their last six encounters with Welsh regions, while the Ospreys were the most recent Welsh team to win at the famous Belfast venue, doing so in April 2010
- The Ospreys have now gone four successive matches without a win in all competitions; however in the RaboDirect PRO12 the Welshmen have suffered just one reversal in their last ten encounters: 23-13 at Edinburgh on November 23
- The Ospreys only away win since October was a 14-3 triumph over the Newport Gwent Dragons on New Year's Eve
- Ulster have already beaten the Ospreys in Swansea in round 2 this season and are going for a first ever season's double over the Welsh region