Harmon was carted off the field during Thursday's game against the Carolina Panthers after sustaining the injury. He ended his rookie preseason campaign with four tackles and a sack.
The 25th overall pick in the 2025 NFL Draft was anticipated to be a major help for the Steelers' interior defensive line for the upcoming season. But Harmon will now miss at least a quarter of the season - making him eligible to be placed on the injured reserve.
Games that Harmon could miss include: New York Jets (Wk 1), Seattle Seahawks (Wk 2), New England Patriots (Wk 3), Minnesota Vikings (Wk 4), Cleveland Browns (Wk 5), and Cincinnati Bengals (Wk 6).
However, with the now two-week gap until the start of the regular season, Harmon could miss just the first two weeks and avoid being placed on the IR altogether.
A huge bullet dodged for the Steelers. They'll begin their season on September 7th against the Jets.