Linebackers are the backbone of LeBeau's zone-blitz scheme. The wily defensive wizard routinely places his second-level defenders in playmaking positions to create opportunities for the defense; this has been his trademark since he developed the scheme nearly 20 years ago. Recently, however, the Steelers' defense has lost some of its bite, with key players beginning to show signs of age- and injury-related decline. As a result, the Steelers have been forced to break in a host of youngsters at prime spots over the past few seasons. Given the growing pains that naturally occur with young players on the field, it's not surprising the unit's sack production has dipped significantly, dropping from 48 in 2010 to 35 in 2011, 37 in 2012 and 34 in 2013. Numbers like those don't cut it in the AFC.