Graeme's wife Kerry gave birth to their first child Josh in midweek and Sean said: "Bevvy's attitude has been amazing.
"We were facing a real scrum-half crisis but he has devoted all his energy to the team cause. Without him, we would have had literally no cover for the No.9 position."
Sam Pinder will start at scrum-half for Glasgow, with Bevvy set to join the action as an impact sub in the last 20 minutes.