Wales international flanker Dan Lydiate will make his Ospreys debut on Saturday when they host the Scarlets at the Liberty Stadium.
Lydiate, who recently joined the region from Racing Metro, lines up alongside Tyler Ardron and Justin Tipuric in the PRO12 leader’s back-row.
Rhys Webb and Dan Biggar continue their impressive half-back partnership while Eli Walker and Hanno Dirksen are the wings this weekend.
Meanwhile, the Scarlets are set to welcome the return of a number of key frontline players to the starting XV for Saturday’s clash.
The West Wales derby sees Scarlets go head-to-head with table-toppers Ospreys with the visitors keen to secure a victory to get their away form this season up and running and to keep the top-six qualification race alive.
A victory for the Scarlets at the Liberty Stadium will end a seven year itch for the region with the last victory over our regional neighbours at their Liberty home recorded in September 2007.
Scottish international John Barclay makes a return after suffering with a thigh haematoma that has kept him out of the side since the Guinness PRO12 defeat to Connacht in November. Barclay will lead the Scarlets at Liberty Stadium in captain Ken Owens (neck) and vice-captain Scott Williams’ (shoulder sprain) absence.
Full-back Liam Williams has been cleared fit for duty after suffering a sprained ankle in the region’s emphatic victory over Ulster in the European Rugby Champions Cup a fortnight ago, an injury that kept him out of action for the PRO12 clash against Cardiff Blues last weekend.
Former Auckland Rugby captain Hadleigh Parkes makes his first start for the region as he links up with fellow Kiwi Regan King, who made his 150th regional appearance in last weekend’s derby against Cardiff Blues, in centre-field.
Scrum-half Aled Davies will make his 50th appearance for the region as he is likely to face in-form international scrum half Rhys Webb.
In the pack Jake Ball and George Earle link up in the second-row with Aaron Shingler returning to fitness after an illness kept him out of last weekend’s clash.
Form: Ospreys returned to the top of the Guinness PRO12 table with their 31-20 home win over Ulster on Saturday, breaking a six game winless run in all tournaments. Ospreys have won their last eight PRO12 fixtures at Liberty Stadium since Munster were the visitors in round 15 last season and have been victorious in their last 16 encounters with fellow Welsh Regions in the tournament. The most recent defeat to a Welsh side at Liberty Stadium came on a visit by the Dragons in October 2010. Scarlets have slipped to back-to-back defeats in the PRO12 but have not lost three in a row in the competition since this time last year. Scarlets have not won away from home in any tournament since a trip to Treviso in the PRO12 in February whilst they have not upset a fellow Welsh Region at their regular home ground since beating Blues at the Arms Park in December 2012. Scarlets only victory over Ospreys in their last dozen encounters was 22-12 at Parc y Scarlets on Boxing Day 2011, whilst the only occasion that Scarlets have ever been triumphant at Liberty Stadium came on 11th September 2007.
Ospreys: 15 Dan Evans, 14 Hanno Dirksen, 13 Ashley Beck, 12 Josh Matavesi, 11 Eli Walker, 10 Dan Biggar, 9 Rhys Webb, 8 Tyler Ardron, 7 Justin Tipuric, 6 Dan Lydiate, 5 Alun Wyn Jones (c), 4 James King, 3 Dmitri Arhip, 2 Scott Baldwin, 1 Marc Thomas.
Replacements: 16 Sam Parry, 17 Gareth Thomas, 18 Daniel Suter, 19 Rynier Bernardo, 20 Sam Lewis, 21 Martin Roberts, 22 Sam Davies, 23 Aisea Natoga.
Scarlets: 15 Liam Williams, 14 Harry Robinson, 13 Regan King, 12 Hadleigh Parkes, 11 Kristian Phillips, 10 Rhys Priestland, 9 Aled Davies, 8 Rory Pitman, 7 John Barclay (c), 6 Aaron Shingler, 5 George Earle, 4 Jake Ball, 3 Samson Lee, 2 Emyr Phillips, 1 Rob Evans.
Replacements: 16 Kirby Myhill, 17 Wyn Jones, 18 Rhodri Jones, 19 Lewis Rawlins, 20 Will Boyde, 21 Rhodri Williams, 22 Steven Shingler, 23 Steffan Hughes.
Date: Saturday, December 27
Kick-off: 17:15 GMT
Venue: Liberty Stadium
Referee: Marius Mitrea (Italy)
>Assistant referees: Wayne Davies (Wales), Jon Mason (Wales)
Television match official: Derek Bevan (Wales)
Assessor: Les Peard (Wales)