DENVER—The Pittsburgh Steelers will be without Pro Bowl linebacker James Harrison for the season opener against the Denver Broncos on Sunday night.

Harrison is working his way back after undergoing minor surgery on his left knee last month. Chris Carter is slated to start in his place.

The loss of Harrison is a big blow to a stalwart Steelers defense that's also missing safety Ryan Clark, who's sitting out as a precaution because of a blood disorder that's aggravated by altitude.

Running back Rashard Mendenhall (knee) won't play, either. Isaac Redman figures to receive a bulk of the carries.

Rookie running back Ronnie Hillman, receiver Andre Caldwell and defensive lineman Malik Jackson are among the inactive players for the Broncos.