Where has the defense gone?

Posted by ESPN.com's Mike Sando

The first five weeks of the NFL season have forced NFC West defenses into deep soul searching.

The Seattle Seahawks fell 15 places in the NFL's defensive rankings after allowing 532 yards to the New York Giants during a 44-6 humiliation at the Meadowlands.

The St. Louis Rams allowed 1,370 yards and 13 offensive touchdowns in their first three games.

The San Francisco 49ers have struggled in key third-down situations, spending more than 37 minutes out of 60 on the field in two of their three defeats.

Even the Arizona Cardinals, though ranked 12th in yards allowed, can relate to their defenseless divisional brethren. The Cardinals watched Brett Favre toss six touchdown passes during a 56-35 defeat to the New York Jets in Week 4.

"I can't speak for those other teams," 49ers linebacker Patrick Willis said. "For us, it's just attention to detail. And as far as a team lining up against us and whooping our tails, that has yet to be done."

Perhaps, but we've seen enough already this season to draw conclusions about the defenses in this division. None appears good enough to hold up on its own. Each needs significant protection from its offense -- through points and ball control -- to mask flaws.

"The mystery in this whole division is what the hell is wrong with the Seahawks?" said Keith Kidd of Scouts Inc.

A team-by-team look at what ails each defense:

Defense: Cardinals

Rank: 12

Symptoms: Too many big plays allowed in the passing game. The defense ranks 22nd in yards per play, 25th in yards per pass attempt and 19th in third-down conversion rate.

Diagnosis: The Cardinals aren't the same team on defense when pass rusher Bert Berry and strong safety Adrian Wilson cannot play. Both missed the Jets game. Wilson provides toughness and confidence for a secondary that needs both. Injuries at nose tackle have also hurt at times this season.

Second opinion: "When you look at their secondary, it scares me," Kidd said. "I don't like their corners. Adrian Wilson is that dynamic guy where you can move him around. When you have that eighth defender, when you can get him up around the line even if you are playing effectively against the run, it messes with the quarterback. ...

"[Defensive coordinator] Clancy Pendergast runs one of the most sophisticated and complicated schemes in the league. He loves to overload sides and do things on the back end that cause confusion. Do they have the personnel to match up with the Dallas Cowboys? Probably not on the back end. He has to come up with some complexities to get Tony Romo confused and not let Romo see in his presnap read how they are going to match up on the perimeter."

Defense: 49ers

Rank: 21t

Symptoms: Before the 49ers started giving up so many big plays, opponents were dinking and dunking their way down the field. Opponents have routinely put together scoring drives lasting 10 plays or longer.

Diagnosis: The 49ers have patched together a defense with veterans from other teams. Some of their high picks, notably linebacker Manny Lawson, are not contributing. The 49ers' lack of speed at safety is showing. The team has tried to mask it by using cornerback Walt Harris deep in coverage, but even Harris somehow let Randy Moss get behind him.

Second opinion: "This was a statement game [vs. New England] of where the program is in San Francisco, and it's not very good. If Tom Brady plays in that game, it's not even close.

"The pass rush was getting there. It was just the guys downfield on the back end. How do you let Randy Moss get behind you in the secondary? Nate Clements has played pretty well, but Michael Lewis is not a very good player, coverage wise. [New England] did a great job of keeping them off balance by running the ball and running at Justin Smith and mixing in that screen game that they utilized with Ben Watson and Kevin Faulk and taking advantage of that intermediate spacing when you bring that eighth defender in the box."

Defense: Seahawks

Rank: 27

Symptoms: The secondary is giving up far too many big plays. Safety Deon Grant has been inconsistent. Teams have picked on cornerback Kelly Jennings. The pass rush hasn't been nearly as strong as anticipated, minus one eight-sack game against the 49ers.

Diagnosis: This defense might not be as good as the Seahawks thought from a talent standpoint. The Seahawks lack size. They aren't built to hold up for long stretches. This is becoming obvious now that Seattle lacks the ability to score in the passing game. The Seahawks also appear less aggressive on the road from a blitz standpoint.

Second opinion: "It looks like teams have gotten away from Marcus Trufant and gone after Kelly Jennings more," Kidd said. "That leads to Trufant falling asleep and giving up a big play. They have been pushed around so much, and now you are committing that extra defender from a run standpoint and then getting exploited in single coverage."

Defense: Rams

Rank: 31

Symptoms: The Rams have struggled badly in the secondary, giving up long pass plays in every game so far. The defense allowed 18 third-down conversions in 35 attempts over the first three games. Blown coverages in the secondary have become routine.

Diagnosis: The defense lacks depth, talent and confidence. The safeties have been out of position repeatedly, exposing the cornerbacks. The Rams have one of the oldest defenses in the league. They could rally under Jim Haslett -- getting worse isn't really an option -- but the long-term prognosis isn't very good.

Second opinion: "They haven't done a real good job drafting back-end guys," Kidd said. "They had to go get Ricky Manning.

"I have seen [safety] Corey Chavous not being real sound in the proper leverage points down the field. I've seen him take the wrong angle. Those are things that are coachable. Corey Chavous, we had him in Arizona and I know what type of player he is. He is extremely smart and he knows how to diagnose and read routes. Sometimes athletically he is a little bit limited, the speed factor. He has been around a long time."