Many factors could be contributing to the Arizona Cardinals' dramatic defensive improvement over the past six games:
Learning a new system. This narrative blames early-season struggles on adopting a new scheme with a first-year coordinator (Ray Horton) following a lockout. There is logic behind the thinking even though the team was already running a base 3-4 defense and felt good about the transition. Coach Ken Whisenhunt in March: "What Ray has done a very good job of is trying to assimilate his system into our terminology.
2011 Cardinals Defense
That is one less hurdle our players will have to deal with. His scheme might be a little bit different, but at least our alignments, what we are calling our defensive schemes, will not be so foreign to them."
Playing poorer opponents. Cam Newton, Eli Manning, Ben Roethlisberger and Joe Flacco were on the schedule during the first seven games. The team has faced Sam Bradford twice, Alex Smith twice and an injured Michael Vick (minus DeSean Jackson) since then. There's some merit to this thinking, no question. But the Cardinals' defense was arguably at its best in holding Tony Romo and the Dallas Cowboys to 13 points. Romo suffered a season-high five sacks and tossed only one touchdown pass, still his lowest single-game total since Week 8.
Personnel changes. Arizona has given young outside linebackers Sam Acho and O'Brien Schofield additional playing time, with positive results. The chart below shows which Cardinals defensive players have seen the greatest changes in playing time from the first seven games to the most recent six. Hank Gargiulo of ESPN Stats & Information provided the snap counts. I calculated the percentages and point changes. The chart shows only those players with swings of at least 15 percentage points. The playing-time changes have limitations. For example, it's possible the defense would have been even better recently if players with diminished snaps had played more.
Top players healthier. One of the team's best defensive players, inside linebacker Daryl Washington, missed two early starts with an injury. Another, strong safety Adrian Wilson, has steadily gotten better after playing through a torn biceps tendon early in the season. Both players appear healthier. The team did lose second-year nose tackle Dan Williams to a season-ending elbow injury, however.
Peterson emerging. Rookie cornerback Patrick Peterson, the fifth player chosen in the 2011 draft, has four punt returns for touchdowns, two during the last six games. Peterson has also made strides in coverage. The secondary in general has played better. Some of the personnel changes could come into play here as well.
These are a few of the reasons for improvement that come to mind readily. Reporters covering the Cardinals' next opponent, Cleveland, asked Whisenhunt for his take on the subject Wednesday.
"I think they are getting more comfortable with the scheme and understanding how it fits together, how they have to play together," Whisenhunt said. "We tried to put a lot in early in the season and we were making a lot of mistakes and we scaled it back, and we have built from there. It is a confidence thing, too."