Chris Szagola/Associated Press

The Philadelphia Flyers have lost five of their last six games and fallen back from the playoff race after doing some major catching up during the past month or so.

It's quite obvious that the Flyers' problems begin and end with their defense.

The Flyers' blue line is simply not talented enough to hang in today's NHL. They are old, slow, passive and mistake-prone—they seem to be unable to consistently make even simple transition passes.

A lot of people will look at Steve Mason's new three-year contract extension, then see his poor recent numbers, and take that easy and convenient connection to create the narrative that says Philadelphia's goaltender woes continue and all that.

But while Mason hasn't been spectacular, he also hasn't been that bad either. The Flyers defense has been mostly atrocious in front of their goaltender, whether it be Mason or Ray Emery.

The problem with defense is that there's no one statistic that incriminates them. If a goal scorer isn't scoring goals or a playmaker doesn't have many assists, then it's easy to say they are not playing well.

When a goalie has a bad goals against average number, it's often muddied as to where the blame lies, and it's typically shared.

But how to divvy up that split blame is particularly difficult.

It's also possible to take some advanced metrics and see what they say about defensemen. Right now, the Flyers aren't looking so hot in that department, according to this awesome graph over at somekindofninja.com.

It looks like (for the millionth year in a row) Kimmo Timonen is the most advanced metric-friendly defenseman right now, with a corsi-relative rating of 15.5 to lead the team.

But Timonen also takes the most faceoffs in the offensive zone of all Flyers defensemen (57.9 percent), which certainly makes his load a lot easier. And that's understandable for a 38-year-old, although it isn't necessarily good for the hockey team.

Braydon Coburn comes out looking pretty decent with the advanced statistics, as he plays against the best competition of all defensemen, has a reasonable offensive-zone start percentage, a positive corsi relative, and also leads the entire team in ice time.

But after that, things get pretty ugly.

Nicklas Grossmann has a horrendous negative corsi relative of minus-15.3, and everyone else comes up looking pretty short.

Luke Schenn has the label of being a "defensive defenseman"—but that's mostly just because he's slow. He takes 53.4 percent of his faceoffs in the offensive zone, and plays against the second-worst competition after Andrej Meszaros.

Alex Brandon/Associated Press/Associated Press

Mark Streit and Erik Gustafsson also have negative corsi-relative ratings, and neither play against top competition. Gustafsson actually takes a lot more defensive-zone faceoffs than Streit, which is a small testament to his underrated all-around game.

In the normal statistics department, things are pretty putrid as well.

The Flyers' seven regular defensemen (I'm including Gustafsson) have combined for just 17 goals this season, with six of them coming from Streit.

Grossmann has 10 points in 52 games. Coburn has 10 in 53. Schenn has a paltry six points in 50 games. Even Streit, who has scored "a lot" by Philadelphia's standards, is still only the 29th-highest scoring defenseman in the league. Timonen is next at 57th.

The best way to supplement all of these numbers is simply by watching them play—they are slow in their zone, slow coming out of the zone and sloppy with the puck.

When people talk about offensive slumps, the blame is always put on the forwards. But everyone has to realize how much defensemen contribute to the offensive attack.

They are responsible for keeping the puck away from their net, but they are also responsible for starting the rush from their own zone and then joining it to keep the flow heading into their opponents' zone.

This requires deft passing, quick reactions, swift skating ability and some offensive vision—Streit can do this occasionally, but the rest of the Flyers' blue line has struggled mightily with this.

They are also not very good at getting pucks to the net and working things around the point. Streit has a cannon, but other than that, there isn't much to work with.

No other defenseman has a power play goal this year besides Streit, which is almost hard to believe and showcases their lack of creativity.

Despite their offensive shortcomings, they aren't exactly bullies in their own zone either.

Streit and Timonen are pretty much contact-free players, Coburn has to be the softest 6'5", 220-pound defenseman in the league and Schenn can only hit people when he catches up to them, which isn't often.

They often exacerbate these issues by taking bad penalties, which not only give their opponent good offensive chances, but wears down the guys doing the penalty killing.

The exorbitant amount of minor penalties that Philadelphia takes is a team issue, but it is one that could be helped greatly by a better defense. Too often they are beat and forced to hold or trip, and forwards are often nabbed for offenses when they are trying to cover for the defenseman's mistake.

In short, this unit is not just unbalanced, they aren't even good at any one aspect of the game.

Blame is an organizational thing. It starts from the top in the front office, then trickles down to the coach and his players.

Each player, each line and each pairing deserve some blame for the Flyers' struggles. But for anyone watching the games, it has to be apparent that the problems are mostly with the defensemen.

With the current unit they have right now, there's no chance they'll make a run at the Stanley Cup. At this point, Philadelphia fans can only hope that changes will come this offseason.