Pittsburgh Steelers defensive lineman Derrick Harmon will reportedly be out one month with an MCL sprain. 

NFL insider Ian Rapoport reported on Friday, citing sources, that Harmon suffered a MCL sprain during Thursday's preseason game against the Carolina Panthers. Harmon will reportedly be sidelined for one month and is a candidate to begin the year on injured reserve. 

"But could have been worse," Rapoport posted to social media.

The 22-year-old rookie has been a standout in training camp for the Steelers, who listed the rookie as the team's starting defensive end on their depth chart.   

When did Derrick Harmon get injured?

Harmon, the 2025 first-round pick out of Oregon, was carted off the field during the second quarter of the game at Bank of America Stadium. He was put on a cart and taken to the locker room for an evaluation. He was then seen on the bench in the fourth quarter.

Sideline reporter Missi Matthews said on Thursday's broadcast that Harmon walked out of the locker room under his own power to the bench.   

When will Derrick Harmon return?

With Rapoport reporting that Harmon is expected to be out for one month, the defensive lineman could return for the Week 4 game against the Minnesota Vikings on Sept. 28 in Ireland or after the team's Week 5 bye.

But if Harmon is placed on injured reserve, he must miss a minimum of four games. Specifics on his return were not reported on Friday. 

Pittsburgh opens the regular season on Sept. 7 against the New York Jets at MetLife Stadium. The Steelers' full 2025 schedule can be found here.