Sam Costelow makes his long-awaited return to rugby after recovering from a shoulder injury picked up playing against Gloucester in January for the Scarlets final home game of the season against BKT United Rugby Championship leaders Leinster.
The Wales outside half is joined in returning to the side for the vital clash with the Irish side by Wales centre Johnny Williams, who has missed the last three games with a calf issue.
The only other changes to the side that picked up five points in their win over the Dragons at Judgement Day X last weekend are Joe Roberts taking over from Macs Page in the midfield and Ryan Elias swapping with Marnus van der Merwe at hooker.
Scottish international lock Alex Craig will bid his farewell to Scarlets fans before he heads to play at Scotstoun next season with Glasgow Warriors. Also leaving at the end of the season will be Ioan Lloyd, who is joining Cardiff, and former Wales wing Steff Evans, hooker Shaun Evans, half backs Charlie Titcombe and Efan Jones and lock Ed Scragg.
The 30-year-old Steff Evans made 190 appearances for the club and is the joint highest Welsh try scorer in URC history with 74. He also won 13 Welsh caps over his 11 seasons at the club.
“It is a big week, a big occasion, the last home game of the season against a team who are probably in the best form in world club rugby. It is a massive challenge, an opportunity and one we are excited about, especially with three games left and things being so tight in the league,” said Scarlets head coach Dwayne Peel.
“There is a lot of rugby still to be played, and I wouldn’t be surprised if it all goes down to the last week. For us, we have got to be accurate, not allow them to get into the rhythm of their game, be brave and be bold.”
The all-international starting XV will have seen Cardiff pick up five points in beating Munster at the Arms Park to move up into fifth place. Edinburgh’s draw against Zebre moved them ahead of the Scarlets into ninth, but any sort of win for Peel’s win will move them into the top eight.
Leinster are top of the table and have been beaten only once in the URC this season. They have rested a number of their senior Irish players ahead of their Investec Champions Cup semi-final next weekend but will still arrive with 10 internationals a side that will be led by hooker Ronan Kelleher for the first time.