Jack Del Rio was a head coach for the past nine years and will return to the defensive coordinator role he held for just one year in Carolina.
Prior to his time in Carolina, Del Rio was the linebackers coach in Baltimore for three years. Del Rio coached Ray Lewis during three of the best years of his career and Peter Boulware had 32 sacks in three seasons under his direct guidance.
Del Rio is taking over a defense that was coached by a very capable coordinator in 2011, so he should be able to hit the ground running. The addition of Peyton Manning will help Del Rio's defense tremendously.
Unlike his predecessor, Del Rio's defense should play with a lead more frequently.
Playing with a lead is helpful, but so is a full offseason program to get acclimated to the Broncos' personnel. The Broncos have two impressive pass-rushers in Von Miller and Elvis Dumervil, but have questions up the middle.
Del Rio did a great job when he was defensive coordinator for the Carolina Panthers in 2002. The defense ranked second in yards allowed, fifth in scoring and seventh in takeaways. In 2001, prior to Del Rio's arrival, virtually the same defense ranked 31st in yards and 28th in points.
Once he got to Jacksonville, Del Rio had to expand his responsibilities and the defenses in Jacksonville were inconsistent, but only rarely bad. Del Rio's worst defenses in Jacksonville were also recent, from 2008 to 2010, but he quickly rectified the defense and the Jaguars had a top-10 defense in 2011.
On the surface, it appears that Del Rio has a track record for turning around bad defenses, but it doesn't always happen in the first year. Del Rio's defense in Jacksonville declined every year from 2006 to 2010 before the 2011 rebound.
If anything, a jump under Del Rio might occur in his second season as defensive coordinator. The Ravens defense made the biggest improvement in Del Rio's second season as linebackers coach and the Jaguars defense also made its biggest improvement in Del Rio's second season as head coach.
Del Rio's dirty secret is that he ran the Jaguars defense in 2009 and 2010, and those were two of the worst defenses during his time as head coach. Mel Tucker was defensive coordinator in title only, and took over the defense in 2011. After that, the defense improved significantly.
Prior to 2009, Mike Smith and Gregg Williams led the defense in Jacksonville. Perhaps Del Rio was stretched too thin as the head coach and defensive coordinator and couldn't give the defense enough attention, but it's notable that the defense improved with him less involved.
Del Rio is also a much more conservative defensive coordinator than his predecessor and would rather avoid the big play and limit the opponent's yardage than take chances.
Don't be surprised when the Broncos improve dramatically in the yardage area, but not significantly in points allowed. The additions of Drayton Florance and Tracy Porter in the secondary should help Del Rio limit the yardage through the air, but the weakness up the middle and at the safety position will make it difficult to stop the running game and limit scoring opportunities for opposing offenses.
If Manning can't get the Broncos a lead, don't expect Del Rio's defense to win the games. But if Manning is as advertised, Del Rio's unit will be statistically strong in 2012.