Scarlets will miss the services of Wales international Leigh Halfpenny for the crucial European Champions Cup encounter against Bath on Friday after the fullback failed a fitness test.
Bath are positioned at the top in Pool 5 but with the third-placed Scarlets trailing just by one point, a defeat at The Recreation Ground for either of the team can dampen their chances of making it to the play-off.
Halfpenny, who sustained a pectoral muscle injury will remain on the sidelines along with Johnny McNicholl, who is recovering from a shoulder injury.
Rhys Patchell will take the place of Halfpenny at fullback while Paul Asquith moves from centre to wing and Hadleigh Parkes lining up alongside Scott Williams in midfield. Dan Jones will don the number 10 jersey.
Scarlets head coach Wayne Pivac said: "We are really looking forward to the occasion. It's a must-win game for both sides. We both know that.
"It's like a knockout game in itself. Competitive people like these sorts of situations, so we are looking forward to it.
"This week has been about trying to get our attacking game going again. We just have to look back to when we played them (Bath) last time. They were more disciplined and more clinical than we were, and played the conditions better than we did."