Despite a seemingly annual procession of high draft picks, the Rams' defensive line always played as less than the sum of its parts, until 2010. The transformation, led by coach Spagnuolo, started by letting go of one high draft pick (underperforming DT Adam Carriker) and not working very hard to entice its best pass rusher (DE Leonard Little) out of retirement. The only additions to the line were a 33-year-old defensive tackle (Fred Robbins) and a pair of third-day draft picks (Eugene Sims and George Selvie). However, these minimal changes had a hugely positive effect on the overall play of the line.
The Rams' defensive line improved radically from 2009 to 2010 by a number of measureable metrics, however, it failed to improve by one key stat:
Sacks: 29th in the NFL (25 total) in 2009 .... 7th in the NFL (43 total) in 2010.
Adjusted Sack Rate (sacks per pass attempt): 27th in the NFL (5.4%) in 2009 .... 8th in the NFL (7.1%) in 2010
Opponent's passer rating: 31st in the NFL (96.9) in 2009 .... 9th in the NFL (80.4) in 2010
Opponent's yards per rush: 20th in the NFL (4.4) in 2009 .... 22nd in the NFL (4.5) in 2010
While moving James Hall (right side) and Chris Long (left side) to their natural positions helped the team take a quantum leap against the pass, the weakness of their interior line couldn't generate any improvement versus the run. Moreover, while most teams utilize rotations with their defensive front four, the constant cycling of players in and out of the lineup at some spots suggests more desperation than plan.
To illustrate this, here is what the Rams' left side of the defense looked like, on a per-snap basis. (Stats via ProFootballFocus.com)