Ruaridh is on the comeback trail after dislocating his shoulder in his one minute appearance in Glasgow's opening day Magners League win over Munster at Firhill.
Ruaridh has been named at full-back in an Ayr team that also includes Glasgow prop Ed Kalman.
Chris Kinloch is in the Currie team to face Melrose at The Greenyards.
Scotland 7s departed the Emirates Airline Dubai Sevens in the Plate semi-final stage this morning having suffered defeat at the hands of Portugal.
An earlier defeat to Wales in the Bowl competition saw tries from Sales Sharks no.8 and Edinburgh winger Andrew Turnbull. Grant Anderson converted one score.
Glasgow’s Hefin O'Hare was the only man to cross the line for Scotland in the Plate semi capping off a disappointing weekend for the Scots.
Following the team’s exit from the competition, coach Stephen Gemmell said: “That’s a real low for me in terms of my involvement with Scotland 7s. We’re not going to make excuses. We let the blue jersey down this weekend.
“There are five guys in this squad who were with us at the World Cup last year and we folded like a proverbial pack of cards.
“The only positive from this experience in that this same group of players, and myself, have an opportunity to go to South Africa next week and lift ourselves back up.”