Scarlets achieved the league double against Cardiff last season and the two sides will play the return fixture at the Arms Park on 12 October.

Scarlets head coach Dwayne Peel: "We have always had close games and battles. Cardiff will be buoyed by the bonus-point win last weekend.

"For the last couple of seasons for some reason we have played Cardiff almost back-to-back, so it seems to be a common theme.

"It is good because it breeds a level of excitement. This game is also a good way to start our home campaign where we want to be difficult to beat."

Cardiff head coach Matt Sherratt: "It is always a challenge and Scarlets beat us twice last year.

"It is always very tough down in west Wales and Saturday will be no different.

"I am sure that [losing twice to Scarlets last season] is at the back of players' minds.

"We will just take it as a new season and a fresh start."

Image source, Huw Evans Picture Agency

Scrum-half Gareth Davies will make his 250th Scarlets appearance to become the third player to achieve the milestone since the inception of regional rugby in 2003, following in the footsteps of prop Phil John and hooker Ken Owens.

"It is a big honour to reach 250 appearances," said Davies.

"There are some big names with that many games, so it's an honour for me to be associated with the likes of them.

"This club means everything to me and I love being here. Hopefully there are a few more seasons left."

Scarlets have had a late change to their front row with the loss of prop Kemsley Mathias so Scotland international Alec Hepburn makes his competitive debut.

Sam O'Connor - younger brother of Harri - steps up to the bench.

Image source, Huw Evans Picture Agency

Cardiff flanker James Botham is injured and replaced by Alun Lawrence, who comes in at number eight with Ben Donnell shifting positions.

It is one of two changes from the side that beat Zebre 22-17 with Wales prop Corey Domachowski replacing Danny Southworth.

Scrum-half Ellis Bevan returns from injury and is named among the Cardiff replacements, alongside fellow Wales number eight Mackenzie Martin.

Cardiff: Cam Winnett; Mason Grady, Rey Lee-Lo, Ben Thomas, Iwan Stephens; Callum Sheedy, Aled Davies; Corey Domachowski, Liam Belcher (capt), Keiron Assiratti, Josh McNally, Teddy Williams, Ben Donnell, Dan Thomas, Alun Lawrence.

Replacements: Evan Lloyd, Ed Byrne, Rhys Litterick, Rory Thornton, Mackenzie Martin, Ellis Bevan, Tinus de Beer, Harri Millard.

Scarlets welcome back captain Josh Macleod from a nine-month injury absence.

The Wales flanker will make his first appearance since January after suffering a knee injury against Clermont.

Macleod's return is one of the changes from last weekend's 20-20 draw at Benetton with fly-half Sam Costelow, prop Henry Thomas and hooker Ryan Elias starting.

Macleod, 27, replaces the injured Vaea Fifita who will miss the next "couple of weeks" after suffering a knee injury out in Treviso.

With Macleod lining up in his preferred number seven role, Jarrod Taylor switches to blind-side flanker with Taine Plumtree moving to number eight.

Thomas will make his Scarlets debut after his arrival from Castres, while former Exeter prop Alec Hepburn could make his first appearance from the bench after recovering from a hamstring problem.

Costelow's return from illness has prompted a backline reshuffle with Ioan Lloyd switching to full-back and Tom Rogers reverting to wing, with centre Eddie James included among the replacements.

There was also a late change before kick-off, with Alec Hepburn promoted from the bench after Kemsley Mathias' withdrawal, and Sam O'Connor named as a replacement.

Scarlets: Ioan Lloyd; Tom Rogers, Macs Page, Johnny Williams, Blair Murray; Sam Costelow, Gareth Davies; Alec Hepburn, Ryan Elias, Henry Thomas, Alex Craig, Max Douglas, Jarrod Taylor, Josh Macleod (capt), Taine Plumtree.

Replacements: Marnus van der Merwe, Sam O'Connor, Sam Wainwright, Jac Price, Dan Davis, Efan Jones, Eddie James, Ellis Mee.

Welcome to the second Welsh derby in the United Rugby Championship this season as Scarlets host Cardiff in Llanelli.

Both sides faced Italian opposition on the opening weekend with Cardiff securing a 22-17 bonus-point home win against Zebre and Scarlets picking up an encouraging 20-20 draw in Treviso against Benetton.

So both sides will be buoyed going into this derby date.