Steelers' Nate Herbig: Out for extended period

Herbig will be out for an extended period of time with a significant shoulder injury, Gerry Dulac of the Pittsburgh Post-Gazette reports.

Herbig's status for Saturday's preseason game was questionable, but now his missed time could even bleed into the season. Rookie Zach Frazier should slide into the center position and fill in while Herbig is sidelined.