The defending Guinness PRO12 champions sealed an 82-12 victory over Scarlets Premiership Select at Llandovery in their first warm-up game of the campaign.
And head coach Pivac has rewarded a number of players who impressed in that game with a second bite at the cherry. Rhys Jones, Tom Grabham, Paul Asquith and Morgan Williams remain in the backline alongside centre Hadleigh Parkes who captains the side.
Dan Jones and Aled Davies start as halfbacks, with Wales internationals Samson Lee, Scott Williams, Gareth Davies, Aaron Shingler, Ryan Elias, Wyn Jones and Steff Evans on the bench.
“It will be a good test and it is at the stage of pre-season where we need this test,” said Scarlets hooker Emyr Phillips of the game with Bristol.
“With Gloucester to come next week we have two good hit-outs and we will see where we are going into the league.”
Pivac, who is preparing his team for the start of the newly expanded Guinness PRO14 season, added: “We are in good shape, the internationals have come back in much better shape than last season. We should hit the ground running.
“We were zero from three at the start of last season and we are looking to turn things round. The next couple of weekends will sort us out against good opposition.
“Bristol, with Pat Lam there now and everyone looking to impress, will be a very good test for us.”
Bristol, who are firm favourites to win the English Championship this season, have named a strong 36-man squad.
Former Scarlets Rhodri and Jordan Williams are named, while Alapati Leiua could make his first appearance in a Bristol shirt.
Ireland ace Ian Madigan is set to start at fly-half.
“The Scarlets play a brilliant brand of rugby as we saw at the end of last season,” said Bristol head coach Lam.
“They’ll be a stiff test for us, but it’s one we’re looking forward to.”
Scarlets XV vs Bristol: Rhys Jones; Tom Grabham, Paul Asquith, Hadleigh Parkes (capt), Morgan Williams; Daniel Jones, Aled Davies; Dylan Evans, Emyr Phillips, Simon Gardiner, David Bulbring, Tom Price, Tom Phillips, Shaun Evans, Josh Macleod
Replacements: Ryan Elias, Wyn Jones, Werner Kruger, Samson Lee, Lewis Rawlins, Tadhg Beirne, Aaron Shingler, James Davies, Will Boyde, Gareth Davies, Rhys Patchell, Scott Williams, Steff Evans, Tom Prydie, Johnny McNicholl
Bristol squad – Forwards: Ross McMillan, Max Crumpton, Jason Harris-Wright, Gaston Cortes, Tyler Gendall, Jack Cosgrove, Soane Tonga’uiha, Jack O’Connell, Joe Joyce, Joe Batley, Joe Latta, John Hawkins, Ehize Ehizode, Nick Fenton-Wells, Olly Robinson, Nick Haining, Dan Thomas, Jordan Crane, Jack Lam
Backs: Jordan Williams, Mat Protheroe, Ryan Edwards, David Lemi, Luke Morahan, Alapati Leiua, Tusi Pisi, Thretton Palamo, Will Hurrell, Siale Piutau, Tom Varndell, Billy Searle, Callum Sheedy, Ian Madigan, Reiss Cullen, Ryan Glynn, Rhodri Williams
