ESPNMiami Dolphins: Can Mike Nolan do for this team what he did for the 2009 Denver Broncos?
Defensive coordinator Mike Nolan helped turn around the Broncos' defense after a terrible 2008 season, so it was a bit of a surprise when the franchise announced he was leaving after just one year. Denver's loss is Miami's gain. If Miami improves in 2010 as much as Denver did in 2009, the Dolphins might have the league's best defense. But don't expect Nolan to work the same miracles.
At FootballOutsiders.com this past season, I took a look at the history of poor defenses that hire well-regarded defensive coordinators. A number of defenses saw big improvement this past season after hiring big-name defensive coordinators such as Nolan, Gregg Williams (New Orleans) and Dom Capers (Green Bay). But surprisingly, 2009 was an exception, not the norm.
The trend search began by looking at the Football Outsiders' advanced DVOA ratings for every team from 1995 to 2008 that had a defensive DVOA above 0 percent (i.e., worse than average) the previous season. You know these teams will improve, on average, because of regression to the mean. But how did teams with new coordinators, in particular experienced coordinators, differ from the larger group of teams coming off bad defensive years? The answer: They didn't. Check this out:
All below-average defenses improved by an average of -5.5 percent DVOA.
All below-average defenses that hired a new coordinator improved by an average of -5.5 percent DVOA.
All below-average defenses that hired a new coordinator with previous coordinator experience improved by an average of -5.3 percent DVOA.
All below-average defenses that hired a new coordinator who previously was coordinator of a top-ten defense improved by an average of -4.0 percent DVOA.
It will be hard for Nolan to have a huge impact on Miami's defense because it wasn't that bad in the first place. The Dolphins were barely below average last season, ranking 18th in DVOA. That's a far cry from the Broncos, who were coming off a season with one of the worst defensive DVOA ratings in history.
The personnel circumstances in Miami are also much different from what Denver's situation was a year ago. Nolan was getting Denver's best defensive player (Champ Bailey) back from injury, and the Broncos signed free agents to fill the three other spots in the starting secondary. Miami, however, isn't getting any new defensive backs. There's no reason to believe the safeties on the free-agent market are any better than Yeremiah Bell or Gibril Wilson, and the Dolphins aren't going to let veterans get in the way of developing the two cornerbacks they took early in last year's draft, Vontae Davis and Sean Smith.
Of course, top-drafted cornerbacks usually take three or four years to develop, not two. So don't be surprised if Miami's defense does improve significantly -- in 2011.