Gregor, who joined the club at the start of last season, suffered an ACL injury meaning he missed the whole campaign but is now back to full fitness and training with the squad and turning out for Glasgow Hawks.
He was part of the Glasgow Warriors squad which won the Melrose 7s in April.
The 22-year-old made 16 appearances for Edinburgh and has come through the Scotland age-grade ranks. In 2012 he was awarded the Macphail Scholarship and spent four months playing club rugby in New Zealand.