In 1996, the Denver Broncos were the 2nd ranked defense in the league (as rated by Football Outsider’s DVOA measure), while the previous year they were 28th. Many members of this board have hoped for a similar defensive turnaround for the 2009 Broncos. On the other hand, the relevance of this example in the current NFL environment has also been drawn into question. Thus, I thought it would be interesting to look at some other teams that have managed to turn around bad defenses.  I’m hoping to do a series of case studies presented as an ongoing feature during the off-season (hopefully with some help from these teams bloggers) with the intention of identifing some common themes from other successful defensive rebuilds.

So what have been the most notable defensive rebuilds?  I'll restrict my focus to teams since 1995.  This allows me to include the 1996 Broncos and also corresponds with the dates of the DVOA database.  I'm using rankings of total defense DVOA as a convenient and reasonable single-valued measure of defensive quality.

There have been 9 year-to-year changes in rank that are greater than 20 since 1995, but most of these large changes have been a "bad" year sandwiched between other good years, and in my opinion don't really count as a rebuild.  For example, Saint Louis went from 3rd in 1999 to 26th in 2000 to 5th in 2001.  Others are the 1997 Raiders, the 2004 and 2007 Redskins, and the 2006 Colts.  Thus, I'll define rebuild somewhat subjectively.  This may include a rapid year-to-year change,but I'm also interested in marked but more gradual improvement
(e.g. Indianapolis Colts from 2001 - 2005).

So without further ado, here is my list of Top 10 Defensive Rebuilds. Please let me know if you think I've missed any that should be considered.

(team:  year, rank. defensive coordinator during turnaround year): 
DEN:  1995, 28; 1996, 2, 1997, 7.  (Greg Robinson, 1995-2000)
MIA:  1996, 20; 1997, 27; 1998, 1; 1999, 9. (George Hill, 1998-1999)
PHI:  1997, 15; 1998, 26; 1999, 7; 2000, 8. (Jim Johnson, 1999-Present)
CLE:  1999, 30; 2000, 25; 2001, 3; 2002, 10. (Foge Fazio, 2001-2002)
BUF:  2001, 27; 2002, 24; 2003, 7; 2004, 1. (Dick LeBeau, 2003)
GB:  2004, 29; 2005, 22; 2006, 6; 2007, 15. (Bob Sanders, 2006-Present)
JAC:  2001, 22; 2002, 25; 2003, 10; 2005, 10. (Mike Smith, 2003-2007)
IND:  2001, 30; 2002, 23; 2003, 15; 2004, 19; 2005, 8. (Ron Meeks, 2002 - Present)
MIN:  2004, 32; 2005, 19; 2006, 4; 2007, 17; 2008, 3. (Mike Tomlin, 2006)
TEN:  2005, 32; 2006, 24; 2007, 1; 2008, 5. (Jim Schwartz, 2001-Present)

Disclaimer: The fact that Bob Slowik had been coordinator on two of
these teams prior to the rebuild did not influence my selections.