Ruaridh returned to his former club earlier this month after three years in the English Premiership with Wasps and Harlequins.
Scotland internationals Lee Jones and Rory Hughes start on either wing, while Nick Grigg makes his first appearance since Scotland's summer tour and will partner Sam Johnson in midfield.
It is the same half-back partnership which started the narrow defeat to Northampton last weekend, with Adam Hastings at fly-half and George Horne at scrum-half.
Jamie Bhatti, James Malcolm and D'arcy Rae once again pack down in the front-row, while Brian Alainu'uese and Scott Cummings combine in the second-row.
Lewis Wynne and Chris Fusaro will start at blind-side and open-side respectively, with Adam Ashe once again captaining the side from Number 8.
George Turner and Lelia Masaga could make their debuts from the bench, while Henry Pyrgos and Peter Horne are set to make their first appearances since touring with Scotland.
14 Lee Jones
13 Nick Grigg
12 Sam Johnson
11 Rory Hughes
10 Adam Hastings
9 George Horne
1 Jamie Bhatti
2 James Malcolm
3 D'arcy Rae
4 Brian Alainu'uese
5 Scott Cummings
6 Lewis Wynne
7 Chris Fusaro
8 Adam Ashe (Captain)
Substitutes
16 George Turner
17 Gary Strain (Glasgow Hawks)
18 Adam Nicol
19 Greg Peterson
20 Kiran McDonald
21 Hamilton Burr
22 Matt Smith
23 Matt Fagerson
24 Henry Pyrgos
25 Peter Horne
26 Patrick Kelly
27 Lelia Masaga
28 Stafford McDowall