Derrick Harmon’s first NFL preseason ends early with a right knee sprain, and Pittsburgh coach Mike Tomlin labeled it week to week after an MRI. The Steelers are hopeful for a September return, but the injury tests their interior DL depth, likely elevating Isaiahh Loudermilk and Yahya Black as the next options. The Panthers’ Raheem Blackshear enters the backdrop as a contrasting run-game note while Harmon focuses on rehab and regaining field time before Week 1 vs. the Jets.