The uncapped 25-year-old will be in a Scotland match-day 23 for the first time after his Warriors team-mate, Dougie Hall, was ruled out through the knee injury he sustained against England.
Scotland team doctor James Robson said: �Dougie has a mild strain of his knee which will not settle in time for this weekend�s game.�
Pat said: �It�s a huge honour to have the chance to play for my country. It�s something I�ve dreamed about since I started playing mini rugby at Ayr and aimed for since I became a professional with Glasgow Warriors.�
Meanwhile, there is better news on Scotland flanker Alasdair Strokosch. Dr Robson said: �Alasdair was seen by a specialist at the Spire Murrayfield Hospital this week and the injury was diagnosed as a fracture of the orbital floor (the area around the eye).
�Alasdair is returning to his club in France and will be in their care. If he has no complications he should be available to return to action in four weeks� time.�