Both changes are in the pack: tighthead prop Craig Dunlea replaces fellow Kiwi Deacon Manu, while Adam Jones moves to the second row from the replacements bench, swapping with Vernon Cooper.
In a positional switch, versatile Inoke Afeaki moves from the back row to the second row to partner Jones.
The Scarlets will go to the Borders in a confident mood as they haven't lost to the Scottish side in their previous eight encounters.
"We've looked at this time of year and hoped to get maximum points," Scarlets skills coach Robert Jones told BBC Sport Wales. "We started with five points against Munster. If we can get a win and perhaps even a bonus point at Borders, it will keep our momentum going whilst the international players are away."
Borders will be without the services of Scotland hooker Ross Ford, serving a seven-day ban for punching in his side's Heineken Cup loss at Northampton.
Scarlets: Barry Davies, Dafydd James, Regan King, Matthew Watkins, Darren Daniel, Ceiron Thomas, Clive Stuart-Smith, Iestyn Thomas, Aled Gravelle, Craig Dunlea, Inoke Afeaki, Adam Jones, Jonathan Mills, James Bater (c), Nathan Thomas
Replacements: Deacon Manu, Ken Owens, Lou Reed, Vernon Cooper, Liam Davies, Morgan Stoddart, Garan Evans
Referee: Olan Trevor (Ireland)