Over the past few years, the Carolina Panthers have been known for a stifling defensive line that averaged 43 sacks between 2002 and 2006. But in 2007, the Panthers totaled just 23 sacks. The worst decline was seen in star defensive end Julius Peppers, who managed a measly 2.5 sacks after posting 13 in '06.
Peppers' mysterious ineffectiveness is just one of many questions revolving around the Panthers' defense this year. Carolina has to deal with Mike Rucker's retirement and Kris Jenkins' departure, and little happened in the offseason to fill those gaping holes in the defensive line. Can Panthers fans hope for a big defensive rebound anyway? We looked at other teams who suddenly lost the ability to rush the passer, using our Football Outsiders stats for Adjusted Sack Rate, which measures sacks per pass play, adjusted for situation and opponent.
The Panthers' ASR dropped from 8.0 percent in 2006 (eighth in the NFL) to 4.8 percent last year (30th), one of the five largest drops since our ASR stats began in 1997. One of the other teams among the five largest drops also played last year -- the Buffalo Bills -- who went from an ASR of 8.1 percent in 2006 to 4.7 percent in 2007. Let's look at other pass defenses with similar drops to see if there's any hope for a miracle turnaround by the Panthers or Bills.
1998-99 Green Bay Packers
1998: 53 sacks, 8.9 percent ASR (1st in NFL)
1999: 29 sacks, 4.8 percent ASR (31st)
What Happened? Defensive coordinator Fritz Shurmur followed head coach Mike Holmgren to Seattle in 1999. More importantly, Hall of Fame defensive end Reggie White, whose 16.0 sacks in 1998 marked the third-highest total of his career, retired after the 1998 campaign. Keith McKenzie and Vonnie Holliday each had 8.0 sacks in 1998, but the Pack wouldn't have another double-digit sack master until Kabeer Gbaja-Biamila registered 13.5 in 2001.
Did They Rebound? No. The Packers had a better pass rush in 2000, but it was still slightly below average (20th in the NFL).
2000-01 Tennessee Titans
2000: 55 sacks, 9.7 percent ASR (2nd)
2001: 33 sacks, 5.4 percent ASR (28th)
What Happened? Sack leader Jevon Kearse's totals didn't decline that much -- from 11.5 in 2000 to 10.0 in 2001 – but his supporting cast couldn't keep up. The Titans fell back to earth after trailing only the historically great Ravens defense in 2000. Ex-Rams lineman Kevin Carter suffered various injuries and registered only two sacks after leading the NFL with 39 over the previous three seasons. Lesser-known players like Kenny Holmes (8.0 sacks in 2000, 3.5 sacks in 2001) also dropped off.
Did They Rebound? Yes. Carter had 10.5 sacks in 2002. Kearse missed 12 games with a foot injury, but rookie seventh-rounder Carlos Hall had three sacks in his first NFL game and finished the year with eight.
2004-05 Kansas City Chiefs
2004: 42 sacks, 9.0 percent ASR (2nd)
2005: 28 sacks, 5.1 percent ASR (29th)
What Happened? That Titans defense and this Kansas City defense have a common denominator: Gunther Cunningham, who coached Tennessee's linebackers from 2001 through 2003 after a short stint as the Chiefs' head coach. Cunningham returned to Kansas City in 2004 as defensive coordinator, and built a great pass rush around rookie Jared Allen and his nine sacks. Allen's total increased in 2005 to 11.0, but nobody else could find the quarterback. Allen was one of seven players with at least 2.5 sacks in 2004, but Allen and Eric Hicks were the only Chiefs with 2.5 sacks or more in 2005. Carlos Hall, so great for the 2001 Titans, had only one sack for the 2005 Chiefs.
Did They Rebound? Not in 2006, when they ranked 28th in Adjusted Sack Rate. However, the Chiefs ranked third in the NFL last year, primarily due to Allen's league-leading 15.5 sacks. With Allen now in Minnesota, the Chiefs hope that third-year end Tamba Hali can replace that production.
1997-98 Jacksonville Jaguars
1997: 49 sacks, 9.0 percent ASR (6th)
1998: 29 sacks, 5.5 percent ASR (29th)
What Happened? The 1997 Jaguars had no double-digit sack artists in 1997, but 14 different players had at least one sack. Clyde Simmons led the team with 8.5, but was a salary-cap casualty after the season and signed with Cincinnati. The lack of an elite pass-rusher hurt when the depth didn't impress in the follow-up year.
Did They Rebound? With a vengeance. Tony Brackens, Kevin Hardy and Gary Walker all had 10 or more sacks under new defensive coordinator Dom Capers, and the Jags boasted the second-best ASR in the league in 1999.
2001-2002 Cincinnati Bengals
2001: 48 sacks, 7.7 percent ASR (6th)
2002: 25 sacks, 4.8 percent ASR (25th)
What Happened? The 2001 total was slightly skewed due to a December game against the Jaguars, when the Bengals amassed eight sacks and tied a team record. In addition, five different players (including rookie Justin Smith) had at least five sacks in 2001. Only Smith and defensive tackle Tony Williams repeated with at least five sacks in 2002.
Did They Rebound? Not really. There was a slight uptick to around the league average in 2003, then another serious decline. Smith was the only constant, but he registered only two sacks last season before signing with the 49ers in free agency.
There are five other teams since 1998 that saw their Adjusted Sack Rate drop by more than one-third from one season to the next:
1999-2000 Detroit Lions
2000-2001 Washington Redskins
2001-2002 New Orleans Saints
2002-2003 Chicago Bears
2004-2005 Denver Broncos
Each of these teams had a better pass rush the following year, but they generally rebounded to around the NFL average, not to their high level of performance from before.
Recent history suggests that the Panthers (and Bills) will have average pass rushes in 2008, but not great ones. However, Panthers fans can take hope from the most similar team on this list. Like the Panthers, the 2001 Titans were stuck with a superstar having an unexpectedly bad season. Neither Kevin Carter nor Julius Peppers missed extended time, but they just couldn't get to the quarterback. Carter made a definitive return to form the next season; perhaps Peppers will do the same.
Doug Farrar is a writer for FootballOutsiders.com and co-author of Pro Football Prospectus 2008, available in bookstores now.