The Steelers reverted Jack to the practice squad Monday, per the NFL's transaction log.
In his second elevation of the season, Jack played all 49 defensive snaps with Elandon Roberts (pectoral) ruled out. Jack finished Sunday's 30-23 win over the Seahawks with eight tackles (seven solo), and he is up to 14 tackles in his two appearances this year. Jack figures to be called up once again for the Steelers' regular-season finale against the Ravens on Jan. 6.