Flanker Hardie returns to the fold for the time since being banned for three months by club-side Edinburgh for gross misconduct and he will be hoping to add to his 16 caps at the Aviva Stadium this weekend.
Lock Gray has also been included in Gregor Townsend's squad for the first time this year following a calf complaint, while Fraser Brown, Zander Fagerson, Alex Dunbar and Darryl Marfo have returned to the fold following spells on the treatment table.
Glasgow Warriors scrum-half is another new name in the squad, as he has been called up for the first time, but he will be a familiar face to many, as he is the brother of fellow squad member Pete Horne.
Magnus Bradbury, Byron McGuigan and Lee Jones complete the list of returning players, although there is no place for either Tim Visser or Rob Harley, who have been ruled out with respective head and wrist injuries.
Scotland beat England last time out at Murrayfield and they can draw level with Ireland at the top of the standings if they can secure a victory in Dublin this weekend.