The Steelers elevated Jack to the active roster Sunday.
Jack will join Pittsburgh's 53-man roster for the fourth week in a row. The 28-year-old linebacker temporarily retired ahead of the season, but he's taken on a notable role since rejoining the Steelers' practice squad in November. Jack has played at least 60 percent of defensive snaps in each of the past three games, tallying 17 tackles and one sack over that span. He figures to once again play as many, if not more, snaps than fellow inside linebackers Mykal Walker and Elandon Roberts during Monday's wild-card matchup versus Buffalo.