Ospreys have been boosted by the news that Wales prop Adam Jones is fit to start their New Year's Day clash against Cardiff at Liberty Stadium.
Jones left the field during the Ospreys' 22-14 defeat to the Scarlets on Boxing Day which immediately raised concerns over the tight-head's fitness ahead of the Six Nations.
Shane Williams will undergo a late fitness test on a shoulder injury and has been bracketed with Hanno Dirksen.
"We're up against a team of international players who have been in outstanding form and will believe that they can come to our patch and get a result," said Ospreys Director of Coaching, Scott Johnson
"Of course we were disappointed to miss out against the Scarlets but that doesn't mean there's been long faces in training this week. The prospect of another derby against such a good team, in front of our own fantastic fans, has made sure of that. There are guys in the team who were pretty down on Boxing Day, that's only natural, they are human beings who are passionate about this region and the defeat hurt them, but the good thing is that hurt is driving them on to do better this weekend.
"We've had a good few days in training, the spirit is good and there's a determination to go out and do the right thing for the cause. No doubt the Blues will make it tough for us, it should be a cracker, but if we make that pass stick, eradicate the unforced errors, make that tackle, then we can get our performance level where it needs to be. If we do that, with our fans really getting behind the team, then it could be derby to remember."
Meanwhile, Cardiff have made five changes. There is one change in the backs with Gavin Evans starting at inside centre in place of Dafydd Hewitt, who is out with a hamstring injury.
There are two changes in the backrow with Josh Navidi and Maama Molitika both starting, Sam Warburton and Michael Paterson moving to the bench. The second row in unchanged but the Blues start with two new props: Scott Andrews and John Yapp both starting in place of Taufa'ao Filise, who is out with a shoulder injury, and Gethin Jenkins who is out with illness.
Jamie Roberts was not available for selection having suffered a knee injury in the win against the Dragons, however, he should be available for selection for the Heineken Cup match against London Irish.
Chris Czekaj, Richard Mustoe and Tom James were also unavailable for selection with hamstring injuries but should all should be available in the next week or so.
Form: Ospreys have slipped to three straight defeats in all competitions, but are unbeaten in three of their last four games in the RaboDirect PRO12. Ospreys have lost just once at home in the tournament since October 2010: 20-22 to Munster on 23 April 2011. Cardiff Blues' last six games in all competitions have all been won by the home side on the day, whilst the Blues have won four of their last five fixtures in the RaboDirect PRO12. Cardiff Blues have not won away from home against a fellow Welsh region since a visit to Dragons on 23 April 2010. The Blues have recorded just one victory over Ospreys in their last four encounters, whilst their only previous win on Ospreys soil was 28-9 on their first visit to Liberty Stadium on 22 December 2005.
Ospreys: 15 Barry Davies, 14 Tommy Bowe, 13 Andrew Bishop, 12 Ashley Beck, 11 Shane Williams/Hanno Dirksen, 10 Matthew Morgan, 9 Kahn Fotuali'i, 8 George Stowers, 7 Justin Tipuric (Capt), 6 James King, 5 Jonathan Thomas, 4 Ryan Jones, 3 Adam Jones, 2 Richard Hibbard, 1 Ryan Bevington.
Replacements: 16 Huw Bennett, 17 Duncan Jones, 18 Aaron Jarvis, 19 Tom Smith, 20 Joe Bearman, 21 Rhys Webb, 22 Dan Biggar, 23 Tom Isaacs.
Cardiff Blues: 15 Gavin Henson, 14 Leigh Halfpenny, 13 Casey Laulala, 12 Gavin Evans, 11 Alex Cuthbert, 10 Ceri Sweeney, 9 Lloyd Williams, 8 Xavier Rush, 7 Josh Navidi, 6 Maama Molitika, 5 Paul Tito (c), 4 Bradley Davies, 3 Scott Andrews, 2 Ryan Tyrell, 1 John Yapp.
Replacements: 16 Marc Breeze, 17 Sam Hobbs, 18 Ryan Harford ,19 Michael Paterson, 20 Sam Warburton, 21 Richie Rees, 22 Dan Parks, 23 Harry Robinson.
Date: Sunday, January 1
Venue: Liberty Stadium
Kick-off: 18.30 GMT
Referee: Nigel Owens