During training camp, Jaguar fans made sure to be cautious with their hopes for the 2009 season. It was understood that this was to be a rebuilding year, and that although improvement over the course of the year was what to be expected, the playoffs were not. After all this was a team featuring four rookie starters in week One of the season. Two of those rookies, Derek Cox and Terrance Knighton, were on a defense trying to recover from a poor 2008 season in which the unit finished 21st in the league.
The defense struggled out of the gate, losing a great player in Reggie Hayward, but an improvement has been evident and the fans are seeing it. Charting the team's performance is difficult to get fair results because a hugely valuable player in Rashean Mathis has been missing with finger and groin injuries. This is what the improvement of the defense has looked like while Rashean Mathis has participated:
The black lines are the best fit trend-lines that show the improvement. Most of the improvement has come from the pass defense in this chart. The improvement is very evident and steady.
In the next chart, the performances while Rashean Mathis was inactive. They will be evaluated in the exact same format:
In this chart, the rushing defense is clearly the unit showing improvement, while the passing defense is the one staying even. Now this doesn't mean that Rashean Mathis is, by any means, a hindrance to the growth of the running defense or a poor rush defender. A rational explanation for this is that the opposing offenses were likely attacking the Jaguars' inexperienced secondary and taking rushes away from the offense.
The impact of Rashean Mathis's absence has been very little according to these charts. However, his impact is likely being masked by the improvement of the defensive unit as a whole. What the graphs do show is that it looks like Mathis provides a much more consistent defense for the Jaguars. The defense has been extremely inconsistent with him on the bench.
Make what you will out of the numbers, both with and without Rashean in the lineup. What can't be argued is that the Jaguars defense is improving.