He lines up in midfield alongside Hadleigh Parkes, who made his 50th appearance last weekend.
Canadian international DTH van der Merwe makes a return from illness that has seen him sidelined for the last three games. His return to the wing sees international Liam Williams return to his preferred fullback position.
Gareth Davies, Rhys Patchell and Steff Evans retain their places at scrum half, fly half and wing respectively.
The pack sees the return of Wales tighthead prop Samson Lee, making his first appearance in Scarlets colours since the victory over Newport Gwent Dragons at Judgement Day IV in April. Rawlins comes in to the second row alongside David Bulbring.
Scarlets head coach Wayne Pivac said: "It was a relief to get the first win [last weekend against Connacht]. Hopefully we've broken the shackles a little bit.
"We look forward now to backing that up on the weekend against Treviso. We've got to build on a slow start and make sure that we gather some momentum now.
"Treviso have improved on last year and they're a different side in terms of how they play their game.
"We've won our games in Italy in the past but we've won none of the comfortably, they've all been a struggle and a battle through the 80 minutes. I think one thing that hasn't changed is they're focused on their home games.
They're a definite threat."
Scarlets team to take on Benetton Treviso at Stadio Comunale di Mongo on Saturday 1st October, kick-off 8.05pm local time;
15 Liam Williams, 14 DTH van der Merwe, 13 Hadleigh Parkes, 12 Scott Williams, 11 Steff Evans, 10 Rhys Patchell, 9 Gareth Davies, 1 Wyn Jones, 2 Ken Owens [c], 3 Samson Lee, 4 Lewis Rawlins, 5 David Bulbring, 6 Aaron Shingler, 7 James Davies, 8 John Barclay
Replacements; Ryan Elias, Luke Garrett, Werner Kruger, Rynier Bernardo, Morgan Allen, Aled Davies, Aled Thomas, Steff Hughes
Unavailable for selection: Rob Evans, Dylan Evans, Jake Ball, Gareth Owen, Tom Price, Jonathan Davies, Emyr Phillips, Tadhg Beirne, Will Taylor
Guinness PRO12 Scarlets News
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