CBPS lost out 22-10 when the two teams met at BT Sport Cardiff Arms Park last Sunday afternoon and the coaching team now make seven changes for the return clash at the Mennaye Field in Pool 4.
Centre Thomas is back in the midfield alongside Aled Summerhill who moves into the No.13 jersey with Harry Davies coming in at full back.
Wing Owen Jenkins is named in the starting line-up, after returning from Wales Sevens duty, while a new-look half back pairing will see Gareth Davies and Lewis Jones combine.
Prop Joe Jones is named in the front row, the final changes see call ups for Miles Normandale, Jordan Viggers and USA international Cam Dolan.
Kieron Assiratti, Shane Lewis-Hughes and Tomos Williams return to the squad to take places among the replacements.
Cardiff Blues Premiership Select: 15 Harry Davies, 14 Richard Smith, 13 Aled Summerhill, 12 Adam Thomas, 11 Owen Jenkins, 10 Gareth Davies, 9 Lewis Jones; 1 Brad Thyer, 2 Scott Andrews, 3 Joe Jones, 4 Miles Normandale, 5 Chris Dicomidis , 6 Jevon Groves (c), 7 Jordan Viggers, 8 Cameron Dolan
Replacements: 16 Ashleigh James, 17 Thomas Davies, 18 Kieron Assiratti, 19 Nick White, 20 Shane Lewis-Hughes, 21 Tomos Williams, 22 Callum Hall