DB: We can never know if the change in scheme or change in personnel was the main contributing factor. My sense was that it was a bit of both. In 2012, Matt Birk, Marshal Yanda, Bryant McKinnie and a healthy Kelechi Osemele had a collective rapport and were a stronger group who played with better leverage. Last year's scheme emphasized lead blocking (i.e. fullback lead, H-back lead), taking larger lateral steps before contact to gain leverage at the point of attack and cutting defenders below the knees on the backside. In 2013, backside cut-blocks were rare and largely ineffective. In addition, the offensive line (particularly the interior) struggled to double-team first-level players and combo up to the second level. This lack of post-snap communication forced running backs Ray Rice and Bernard Pierce to evade defenders before reaching the line of scrimmage. I looked at these struggles more in-depth here.