Losing Harrison unquestionably hurts the defense. But it has yet to severely impact the results of games.
Since the start of the 2011 season, the Steelers have done just as well with Harrison (8-3 record) as without him (5-2 record). In a stat that will shock most, Pittsburgh averages slightly more sacks without Harrison. The Steelers have recorded 17 sacks in seven games without Harrison and 22 with him. LaMarr Woodley has sacked the quarterback 8.5 times in the seven games that Harrison has missed.
Where the Steelers really feel the loss of Harrison is in keeping offenses off the scoreboard. In the 11 games with Harrison since the start of 2011, the Steelers have limited teams to 12.7 points including two shutouts. Without Harrison, Pittsburgh has given up 18.2 points.
Harrison hasn't played since a playoff loss in Denver nine months ago. He was sidelined all of training camp with a knee injury, and had arthroscopic surgery on Aug. 15. There's a possibility that he could be available after next week's bye.
Chris Carter, a fifth-round pick in 2011, is expected to start in place of Harrison once again. Backup safety Ryan Mundy would make his third start of the season after replacing Ryan Clark in the season opener and Polamalu last Sunday.