The centre damaged his ankle in Sunday's Heineken Cup defeat to Llanelli after returning from an injury nightmare this season. Andy spent four months out with a knee injury and then another four after he broke down during his rehabilitation.
"It is a massive blow for us and Scotland, but a personal nightmare for Andy," Glasgow backs coach, Sean Lineen, told The Hearld.
"He had just come back from a long lay-off caused by knee surgery to edge his way back into the picture."