Herbig (hamstring) has been downgraded and ruled out ahead of Sunday's matchup against the Lions, Brooke Pryor of ESPN.com reports.
The third-year pro from Wisconsin upgraded from DNPs on Wednesday and Thursday to a limited session Friday, suggesting he was trending in the right direction ahead of Sunday's matchup. However, it now appears he won't be able to suit up for the Week 16 contest. While Herbig is sidelined Sunday, expect Alex Highsmith and rookie Jack Sawyer to operate as the Steelers' top outside linebackers.