SCARLETS (2nd) v ULSTER (1st), Parc y Scarlets, 4pm (live BBC 2 Northern Ireland/RTÉ Two/S4C)
Team News: Ulster head coach Mark Anscombe has made nine changes for the top of the table RaboDirect PRO12 match against the Scarlets in Llanelli on Sunday.
Team captain Johann Muller has returned from a thumb injury to captain the side in one of five changes to the pack, while Ireland hooker Rory Best is fit enough to be named on the bench after overcoming neck problems.
After their exertions in recent weeks, Anscombe has decided to rest back rowers Nick Williams and Chris Henry, in addition to frontline backs Ruan Pienaar, Paddy Wallace and Jared Payne.
Forward trio Stephen Ferris, Lewis Stevenson and Declan Fitzpatrick are all sidelined through injury.
Callum Black and John Afoa will start in the province's front row at Parc y Scarlets, linking up with South African-born hooker Rob Herring.
Neil McComb retains his place in the second row beside the fit-again Muller, with Iain Henderson and Robbie Diack coming in for Williams and Mike McComish. Roger Wilson will again start at number 8.
Ireland squad members Paddy Jackson, Luke Marshall, Darren Cave and Craig Gilroy all come straight back into the back-line after impressing during the November internationals.
Jackson will partner Paul Marshall at half back, while Cave and Luke Marshall will combine in midfield. Peter Nelson will get another run at full-back, with Gilroy and Andrew Trimble lining out on the wings.
A strong bench has been named, including current Ireland internationals Best, Tom Court, Dan Tuohy and Tommy Bowe.
Development prop Ricky Lutton could win his second cap if he appears off the bench on Sunday afternnon, while McComish, Michael Heaney and Niall O'Connor will provide further cover.
Meanwhile, the Scarlets will seek to complete an Irish double after overcoming Munster in wet conditions in Cork last Sunday evening.
That 13-6 victory has kept competition tight between the top six - Ulster currently hold a six-point lead - and the Scarlets know how important a home win could be for their ambitions of a play-off place later in the season.
Scarlets boss Simon Easterby has made changes to his back-three, bringing Dan Newton and Kristian Phillips in for Morgan Stoddart and the benched Nick Reynolds respectively.
The front row, containing Emyr Phillips, the man-of-the-match against Munster, is unchanged while Johan Snyman will start in the second row in place of the suspended Jake Ball.
Kieran Murphy also returns at number 8 with Craig Price dropping to the region's replacements bench.
The Scarlets welcome back three of their squad from international duty all of whom give strength to the bench for Sunday's showdown - Fiji captain Deacon Manu, Tomas Vallejos from Argentina and Wales' Kirby Myhill.
SCARLETS: Dan Newton; Kristian Phillips, Gareth Maule, Gareth Owen, Andy Fenby; Aled Thomas, Gareth Davies; Phil John, Emyr Phillips, Jacobie Adriaanse, Johan Snyman, Richard Kelly, George Earle, Johnathan Edwards (capt), Kieran Murphy.
Replacements: Kirby Myhill, Shaun Hopkins, Deacon Manu, Tomas Vallejos, Craig Price, Aled Davies, Adam Warren, Nick Reynolds.
ULSTER: Peter Nelson; Andrew Trimble, Darren Cave, Luke Marshall, Craig Gilroy; Paddy Jackson, Paul Marshall; Callum Black, Rob Herring, John Afoa, Johann Muller (capt), Neil McComb, Iain Henderson, Robbie Diack, Roger Wilson.
Replacements: Rory Best, Tom Court, Ricky Lutton, Dan Tuohy, Mike McComish, Michael Heaney, Niall O'Connor, Tommy Bowe.
Referee: Peter Fitzgibbon (Ireland)
Assistant Referees: James Jones, Chris Williams (both Wales)
Television Match Official: Nigel Whitehouse (Wales)
Match Odds (Paddy Power): Scarlets to win: 6/4; Draw: 20/1; Ulster to win: 8/15
Pre-Match Quotes: Paul Marshall (Ulster) - "It was nice to be involved (with the Ireland squad), obviously, playing in the Fiji game as well. It's good to be in the set-up and hopefully knocking on the door.
"(Against Treviso last week) we were standing under the posts with a minute to go, trying to plan how we were going to get the ball back because we assumed they were going to get the kick.
"We were thinking, 'How are we going to get one more chance to win the game?' But thankfully they missed the kick and we were able to see out the remaining minute (and get the victory).
"We won the Dragons and Edinburgh games, scoring six tries in both of those games, but we felt, as a team, that we actually didn't play that well.
"But I think if you look at the last couple of games (against Zebre and Treviso) where we haven't played that well, we haven't scored as many tries so we've had to grind the win out.
"I think it shows character that we're able to go points behind but still know that we've got enough in the tank to come back. But you just don't want to be doing that every week - you'd rather be winning by 40 points than scraping home."
Mark Jones (Scarlets) - "They have threats all over the park, so we know we'll have to be at the top of our game. It's going to be a real challenge for us, one we're looking forward to and a great game of rugby is in prospect if the conditions allow.
"Ulster have got plenty of quality in their squad, and also the luxury of calling on their internationals, so we know it's going to be a big test for us and we respect what Ulster have achieved this season.
"While we know we've got stern opposition, we've concentrated on ourselves this week, making sure we have our own house in order.
"We've been working closely with the players to help them improve their reading of the game as it's happening encouraging them to take responsibility and show the mental agility to adapt as they need to.
"Credit to all the boys that haven't been involved in the internationals, they've worked very hard and put in some big performances for the region while a big group of our players were away.
"A number of them have laid down the gauntlet to those returning and that's what we want as coaches to see that competition."
Top Scorers - 2012/13 RaboDirect PRO12: Scarlets - Points: Aled Thomas 48; Tries: George North 7; Ulster - Points: Paddy Jackson 46; Tries: Jared Payne 5
RECENT LEAGUE MEETINGS:
Friday, October 2, 2009 - Ulster 45 Scarlets 24, Ravenhill
Friday, March 5, 2010 - Scarlets 25 Ulster 8, Parc y Scarlets
Friday, February 18, 2011 - Scarlets 16 Ulster 18, Parc y Scarlets
Friday, April 1, 2011 - Ulster 20 Scarlets 18, Ravenhill
Saturday, October 29, 2011 - Scarlets 24 Ulster 17, Parc y Scarlets
Friday, December 2, 2011 - Ulster 24 Scarlets 17, Ravenhill
- The Scarlets have won their last four games in the RaboDirect PRO12. Their only league defeat at Parc y Scarlets in their last 13 fixtures was a 23-16 loss to the Ospreys on September 21
- No Irish province has won at the Llanelli stadium since Leinster were the visitors in September 2011
- Ulster's superb unblemished start to the 2012/13 campaign continues apace with 11 straight wins in all competitions
- The Ulstermen are attempting to complete a clean sweep of victories away from home to the Welsh regions this season
- The last three matches between the two sides have all been won by the home side on the day. Ulster's only win in Llanelli to date came in February 2011