The vastly experienced second row packs down alongside Tom Savage in the second row as Gloucester make four changes from the side that defeated Munster 45-8 at Kingsholm last Saturday.
Three of those changes are in the pack as Yann Thomas takes over from Dan Murphy at loose head and Ross Moriarty features at blindside flanker in addition to Palmer starting.
Behind the scrum, the only change is at scrum half where Dan Robson is back in the number nine shirt instead of Scotland international Greig Laidlaw.
It's Gloucester's final preseason friendly ahead of the Aviva Premiership opener against next Friday evening and skipper Billy Twelvetrees is looking for his team to be tested in West Wales.
"Munster was good but if we are totally honest we probably didn't get tested as much as we would have liked to have done. Defensively we would have liked to have been challenged more but I'm sure the Scarlets will do that.
"They are a very good team in terms of their structure, they don't muck around too much in their half and get rid of the ball, they will challenge our breakdown and then they have a lot of dangerous backs with Regan King, who is a very talented player, back as well.
"But as long as we concentrate on ourselves and get our set-piece and basics going well we will be okay."
Rob Cook; Charlie Sharples, Henry Trinder, Billy Twelvetrees, Jonny May; James Hook, Dan Robson; Yann Thomas, Richard Hibbard, John Afoa; Tom Savage, Tom Palmer; Ross Moriarty, Matt Kvesic, Ben Morgan
Dan Murphy, Aleki Lutui, Shaun Knight, Elliott Stooke, James Hudson, Sione Kalamafoni, Jacob Rowan, Callum Braley, Aled Thomas, Shane Monahan, Mark Atkinson, Tom Isaacs, Henry Purdy, Steve McColl
To follow the action from Parc y Scarlets, visit www.gloucesterrugby.co.uk/live before kick off to keep up to date with the match day live blog, proudly sponsored by Advanced Insulations.
29 - 24
HT: 17 - 10
30th August 2014