Steelers 1st-rounder Derrick Harmon reportedly out ‘about a month’ with knee injury

Pittsburgh Steelers first-round rookie Derrick Harmon has been diagnosed with a knee ligament sprain and will be out “about a month,” according to a report from the NFL Network.

Harmon, a defensive lineman drafted 21st overall, suffered an injury early during the second quarter of the Steelers’ preseason finale at the Carolina Panthers on Thursday night. According to the report, Harmon was diagnosed with an MCL sprain and is a candidate to begin the season on the injured reserve list.

This was Harmon’s last snap before he was taken off. Looks like he fell awkwardly on his right side and got twisted up. pic.twitter.com/IifbWMe4sP

— Brooke Pryor (@bepryor) August 22, 2025

The one-month timetable would mean Harmon would miss the Steelers’ first three regular-season games. Coincidentally, that timeline would make Harmon’s NFL debut the Sept. 28 game in Dublin, Ireland, against the Minnesota Vikings.

The NFL’s IR rules allow for two players to be placed on the list on the final roster cutdown day, which is Tuesday. Any such player would not count toward the 53-man limit and must be one of eight available “designated to return” slots given to each team per season for IR. A player on IR must miss at least four games.

The Steelers have their bye after their fourth game.

Harmon going on IR would open a roster spot for a “bubble” player to make the team.

The 6-foot-4, 313-pound Harmon, drafted out of Oregon, has been impressive at training camp. Already named one of three starting defensive linemen on the team’s initial official depth chart, Harmon had four tackles (one solo), one sack and one tackle for loss over 74 snaps played in three preseason games.

The Steelers had some depth at the bottom of their roster at defensive tackle. Harmon going on IR potentially opens a spot for a player such as Isaiahh Loudermilk or Esezi Otomewo.