Ruaridh, who sustained the injury whilst scoring the only try of the night, will therefore be out of contention for Glasgow's opening two Heineken Cup pool matches in October and the prospects of a debut cap during the Bank of Scotland Corporate Tests against Fiji, Australia and Argentina in November.
Glasgow Warriors team doctor, Gerry Haggerty, said: “Following medical examination on Monday evening Ruaridh will have his shoulder stabilised in the coming week once the injury has had time to settle.
“It will take around three months for the shoulder to heal but our immediate aim is to ensure a full recovery for Ruaridh and to have him back playing for Glasgow as soon as possible.”