Harmon has been expected to be a potential starter right off the bat for the Steelers. However, he went down with an injury that was originally diagnosed as an MCL sprain. That diagnosis would have come with a potential 4-6 week timetable for return.

It's another step in the right direction for the Pittsburgh Steelers rookie, who avoided catastrophe in the preseason finale.

Pittsburgh Steelers first-round rookie Derrick Harmon is expected to miss several weeks following an MRI on his knee.