All the talk about the Giants since their 24–21 exhibition game loss to the Carolina Panthers on Saturday has focused on the defense — or lack thereof. Carolina scored on four of its first five possessions, and the Panthers’ starting running back, DeShaun Foster, gained 62 yards on five carries. The Giants’ first-string defense got off to an ugly start.

But a closer look at the Giants’ defensive performance indicates that although there’s a lot of work left to do, new coordinator Steve Spagnuolo has made real strides in developing a more aggressive, more explosive defense. And far from missing their biggest star, holdout defensive end Michael Strahan, the Giants appear to be building a defense that can operate just fine without him.

From a coach’s perspective, the purpose of the preseason is to evaluate the players and familiarize them with the plays they’ll be running in a few weeks, when the games start to count for real. For Spagnuolo, who’s in his first year with the Giants after eight seasons as the linebackers coach for the Philadelphia Eagles, that means, first and foremost, getting the players accustomed to his emphasis on blitzing the opposing quarterback. And in that respect, the Giants played well against Carolina.

Of the 28 times the Panthers dropped back to pass Saturday, Big Blue recorded four sacks. Several other times, the pass rush got close enough to disrupt the Panthers’ quarterbacks. Defensive back Will Demps, linebacker Zak DeOssie, and defensive end Marquise Gunn each registered a sack, and linebacker Chase Blackburn shared credit for a sack with defensive end Tommy Davis.

That the defensive line accounted for less than half of the Giants’ sack total against Carolina is a good sign, as establishing a pass rush from the linebackers and the defensive backs will be a major emphasis for Spagnuolo’s defense. It will also be a way the Giants can improve from last season, when they rarely got any pass rush beyond their defensive line. (Linebacker Brandon Short had two sacks last year; no other linebacker or defensive back had more than one.)

The pass rush was a strength of the Eagles’ defense and a weakness of the Giants’ defense last year, and changing that is Spagnuolo’s biggest task. Just how different the Eagles’ pass rush was from the Giants’ in 2006 is documented in the “Pro Football Prospectus 2007,” which uses statistics beyond just sacks to quantify a defense’s ability to rush the passer.

For instance, forcing opposing quarterbacks to throw the ball away is an important part of rushing the passer, and in that category, the Giants ranked dead last in the NFL in 2006. The Eagles ranked first in the league. The Eagles’ defense was so good at forcing quarterbacks to throw the ball away that Philadelphia’s opponents had seven intentional grounding penalties last year, or 25% of all the intentional grounding penalties in the entire league. No other team forced the opposing quarterback to be flagged for intentional grounding more than twice.

The Eagles’ success at rushing the passer was the result, in large part, of blitzing more aggressively than most teams do. The Eagles blitzed with six or more players 10.9% of the time last year, ranking eighth in the league. The Giants blitzed with six or more pass rushers on only 3.1% of plays, ranking 30th in the NFL. Spagnuolo intends to make the Giants’ 2007 defense look more like the Eagles’ 2006 defense.

And that leads to the most common question the Giants’ players and coaches faced after the first string defense’s sub-par performance against the Panthers. Everyone wanted to know whether the absence of defensive end Michael Strahan, who is currently holding out of training camp and contemplating retirement, was the reason the defense struggled. But defensive ends Osi Umenyiora and Justin Tuck — who will be the starters if Strahan never reports to the team — looked like natural fits in Spagnuolo’s system. The problems with the Giants’ defense had little if anything to do with Strahan not being there.

Furthermore, the changes Spagnuolo is making to the defense should actually diminish Strahan’s importance. In the last few seasons, the Giants relied primarily on their defensive ends to generate a pass rush, and that made Strahan — one of the best passrushing defensive ends in NFL history — their most important player. But Spagnuolo hopes to get a pass rush from players at other positions, and if he succeeds, the Giants’ pass rush will be fine even if Strahan never plays for them again.

None of this should minimize the problems the Giants’ defense displayed Saturday. They missed way too many tackles, which is a recipe for failure no matter what the defensive scheme, and the secondary often appeared disorganized. But those disappointments also shouldn’t obscure the fact that the preseason opener provided a preview of how the Giants’ defense will look in 2007, and it wasn’t all bad.

Mr. Smith is a contributing editor for FootballOutsiders.com.