One of the biggest contests and most eagerly anticipated games of the season for supporters in the West, the traditional Boxing Day fixture for the Scarlets against their closest rivals never fails to bring added edge and drama.
The Scarlets are facing quick turnaround from their battle on Friday night at the Cardiff Blues, while the Ospreys have had more rest time, not having played since their win over Toulouse in the Heineken Cup.
The Scarlets make four personnel changes to the starting line-up that was victorious at the Arms Park with Aled Davies getting a start back at scrum-half; former Osprey Kristian Phillips comes onto the wing, Matthew Rees starts at hooker and Jake Ball comes into the second row alongside George Earle.
The Ospreys host the Scarlets with a strong home record behind them this season having beenvictorious in their last seven games at Liberty Stadium. The Ospreys have won their last five clashes with fellow Welsh regions.
Scarlets have won five of their last six RaboDirect PRO12 fixtures, the only defeat being against runaway leaders Ulster on 2 December.
The West Wales side will be boosted by their strong form on the road with the Scarlets having won five of their six away fixtures this season in the league - their only away loss in the competition this season was 20-22 at Treviso on 29 September.
Scarlets have won eight of their last nine encounters with fellow Welsh regions. The West Walians last beat Ospreys 22-14 at Parc y Scarlets exactly twelve months ago.
Scarlets Attack Coach Mark Jones said: "There's never any need for motivation for coaches or players for this fixture. We may have had less preparation time but the boys have worked hard on their recovery during the four-day turnaround and they know how significant this game is for us on a number of levels.
"It's going to be a very intense game and a typically physical match. We don't have to cast our minds back too far to our last encounter with the Ospreys and where in the game we came out second best.
"We know the quality the Ospreys have, they'll come out strong will be feeling confident after an impressive win over Toulouse in Europe. It's going to be a high impact and a big battle up front but the players are in the right mindset and we're looking forward to a great contest."
Scarlets outside half Aled Thomas said: "We adjusted our game last weekend, the forwards carried well and made the hard yards for us and overall we controlled territory well. We'll need to step up again for this encounter, the Ospreys have strength across the field but we if can get quick ball to our backs - we know we have the talent do some damage.
"We want to build on that performance this week; it was difficult in the conditions last Friday to play an expansive game but what mattered was four points and keeping our campaign for a play-off place on track.
"We want to stamp our authority on this game and to keep that place - so there's plenty riding on this fixture for both sides. Wins on the road are what count in this competition if you want to make the play-off places."
Scarlets Team v Ospreys Wednesday 26th December kick off 5.30pm Liberty Stadium; 15 Liam Williams 14 George North, 13 Jonathan Davies (capt), 12 Scott Williams, 11 Kristian Phillips, 10 Aled Thomas, 9 Aled Davies, 1 Phil John, 2 Matthew Rees, 3 Samson Lee, 4 Jake Ball, 5 George Earle, 6 Josh Turnbull, 7 Aaron Shingler, 8 Kieran Murphy.
Replacements: 16 Emyr Phillips, 17 Shaun Hopkins, 18 Jacobie Adriaanse, 19 Sione Timani, 20 Rob McCusker, 21 Tavis Knoyle, 22 Gareth Owen, 23 Gareth Maule.
Players not available for selection through injury are Rhys Priestland (achilles), Ken Owens (ribs), Gareth Davies (ribs) and Joe Synman (groin).
After the Ospreys, the Scarlets face another significant away trip to Ulster who at the half way point of the regular season, sit at the top of the RaboDirect PRO12 table with a perfect won 11 out of 11 record. As part of a run of big games for the West Walians, the Scarlets then take on Leinster and Clermont Auvergne in the Heineken Cup.
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