Defenses and defensive players in today’s NFL are increasingly subject to the same statistical analysis as their offensive counterparts. Defensive stats have been in place in some measure for decades, but a defense’s efficiency and effectiveness, like so many other sports in this still-growing stage of appreciating stats of all kinds, haven’t always been subject to the same mathematical spotlight as they are now.

Neither Ray Nitschke nor Clay Matthews need numbers to make their presence felt. The best linebackers are often a form of very aggressive lurkers on the field; always around the play or ball, in the backfield far too often for the offense’s comfort. But in Matthews’ case stats can further illustrate a dominant young career, despite the fact that everyone knows he is the danger on the defensive side for the Packers. At the website ProFootballFocus.com, the impact Matthews makes gets a little more mind-boggling.

“There may not be a more consistent pass rusher who has been so heavily leaned upon to be his team’s lead source of pressure,” Ben Stockwell writes for ProFootballFocus.com. “In each of his four seasons in Green Bay, Clay Matthews has recorded at least 50 total pressures, and at least 25 of those have been hits or sacks.”

ProFootballFocus lists total pressures as the combined number of quarterback sacks, hits and hurries. Matthews had 56 total pressures in 2012.

Stockwell adds: “Ally this with solid run defense and an ability to drop into coverage when required and you not only have a top-line pass rusher but also one of the league’s most rounded 3-4 outside linebackers.”

We could go further in depth, but the point here is that it wasn’t always this way, far from it. Sacks, one of today’s premier stat categories for defenders, weren’t officially counted by the league until 1982. The recording of tackles still remains up for interpretation. Folks weren’t assigning equations to measure a secondary’s skill in making open field tackles down the field — as they do now — when Nitschke played.

Instead people were coming up with fierce trademarks, the sort that warned when a Sunday afternoon could be potentially harmful to the overall wellbeing of the opposition. Nicknames like the Doomsday Defense, Purple People Eaters, Steel Curtain or No-Name Defense vaulted units into something more than one-third of a football team. They were probably not real monsters or cannibals, but more than numbers, defenses were known by their personnel, or personalities, as well as their overall style of play.

Those nicknames, like statistics today, were — other than being pretty awesome — ways people tried to differentiate and better understand teams. Both of these methods can be useful, and they’re not mutually exclusive: the Baltimore Ravens of the recent past are a good example of menacing style and substance to match. No matter a given period’s integration of stats, however, the defenses and players who get the reputations which lead to these imposing, larger-than-life portrayals usually earn them for a reason.

The Nitschke standard

Ray Nitschke didn’t have to have a nickname. Still, the Hall of Fame Green Bay Packers linebacker who played his entire career from 1958-1972 with the team is one such example of mythology being matched by the man. With the current era’s team, the mantle for iconic Packers linebackers is and will likely be held by Clay Matthews for a very long time. But Nitschke built that mantle from the shattered pieces of those he smashed during his career.

They are their own players, to be sure, and this is not about trivially deciding who’s better in some way. Rather it’s an appreciation for Matthews so far and Nitschke’s unending legacy. Even with different takes on the linebacker position, they could wind up sharing similar spots on their respective Packers teams.

We may never know the full effect Nitschke had, statistically speaking, but with him does that matter? It’d be nice, sure, but Nitschke is one of the best incarnations of old-school smash mouth football regardless. He was the heart and soul of Vince Lombardi’s many championship defenses. Nitschke was a magnetic team leader who played with boiling rage on the field.

“He was the man. He played his heart out and he expected nothing less from his teammates, to play as hard as you could on every play,” said his former teammate Dave Robinson. “If we were ahead by 40 points you could never tell because the next play may be the one that breaks the game wide open or gives them momentum.

“Ray got very excited during games, and his enthusiasm and excitement spilled over into the rest of us. He was a very emotional guy.”

Robinson went on: “He once told me, ‘Everything I own, everything I do, everything I’ve seen I owe to football, and I’m going to try and pay it back.’ That’s the way he played: like he was trying to repay a debt.”

Adding to his fiery legend was the way that on-field persona melted into an accessible, diametrically friendly public figure and staple of the Green Bay community off it.

Tom Murphy is the Director and Archivist for the Green Bay Packers Hall of Fame and got to know Nitschke — who was always willing to help the Hall — well over the years.

“He was an intimidating person but in a lot of ways he was a gentle person,” Murphy said. “If you would see him, and you knew him, he was always very warm. And I don’t think he ever turned down an autograph.”

Autographs, in more ways than monetary value, are a big way Nitschke left his mark.

“Marv Fleming mentioned this at the golf outing this year when someone said he had a very clear autograph,” Murphy said. “He (Fleming) said, ‘Well I learned when I was a rookie with the Packers and I was signing an autograph and Ray Nitschke saw what I had written. He pulled me aside and said, ‘Son, you’re going to have to sign it so that people remember you, that’s the least you can do. Sign that so people can read it and they’ll remember you.’”

“Everybody listened to Ray,” Murphy said. Just like Donny Anderson, who played running back and punter for the Packers from 1966-1971, did in his rookie season. Anderson, Murphy said, was used to coming out of the locker room last at Texas Tech, but was quickly warned that that spot was reserved for Nitschke in Green Bay.

“He learned real quick that Ray Nitschke was the last guy to go on the field for the Green Bay Packers,” Murphy said.

And just like John Jurkovic, a defensive lineman for the Packers in the 1990s, did. When Murphy complimented him on his handwriting once at an autograph signing, Jurkovic explained.

“Jurkovic said, ‘When I came to Green Bay I was signing an autograph and Ray Nitschke was looking over my shoulder and he pulled me aside and said, ‘Son, you sign that so they can read it so they’ll remember you, that’s the least you can do,’” Murphy recalled.

“He was a very serious football player, but he was also a very good person,” Murphy said.

It is also easy to omit, because of his wrecking ball-versus-thin wall approach to football, that Nitschke was a playmaker. He picked off 25 passes over his career and had a deceptive speed that allowed him to keep pace with receivers of the time. He began his collegiate career at the University of Illinois as a quarterback, and Murphy says Nitschke, “a terrific athlete,” was rumored to have the strongest arm of anyone on the team during his time.

The Claymaker

Now more than ever especially, Clay Matthews is the essence of whatever this tweaked version of the Packers’ defense will be in 2013. As a unit, Green Bay aims to wield fast and fierce pressurized force, focused on generating offensive mistakes and, when it’s working at its peak potency, turnovers and sacks, meaning more possessions for their dangerous offense. Matthews is pretty much all of that rolled into one player as the Packers’ outside linebacker. His first five seasons in the NFL have been productive and disruptive (42.5 career sacks, 22 passes defensed with four interceptions and seven forced fumbles), his impact only being hindered by a sometimes-nagging hamstring injury, the opposition’s growing emphasis on slowing him down best they can and, as noted above, the lack of consistent help opposite him.

Matthews covers ground and closes on quarterbacks like a cheetah on the Serengeti, his ability to turn the corner at a low angle without losing any speed second to none in the league. He’s forced his share of critical turnovers too, the kind that build a player’s mythos over the years. The most famous to this point probably came when he perfectly popped his shoulder pad into the arm cradle of Pittsburgh Steelers running back Rashard Mendenhall, springing the football from his grasp in the beginning of the fourth quarter of Super Bowl XLV, allowing Desmond Bishop to scoop it up just as Pittsburgh was sapping Green Bay’s momentum and driving for the lead.

“He’s just relentless,” Minnesota Vikings fullback Jerome Felton said of Matthews as part of the NFL Network’s “Top 100 Players of 2013” countdown. “He works hard, he doesn’t get tired, he’s athletic and fast, he’s physical, he just has the biggest motor combined with athleticism I’ve seen in the game.”

After inking a five-year, $66 million contract extension this offseason — the most lucrative deal in the league for any linebacker — Matthews is the face of the Packers’ defense for the foreseeable future. Not that he wasn’t before. Now though, with Charles Woodson gone, the leadership role — that hard to pin down non-statistic — for the unit has opened wide for Matthews to step in. It’s a topic that will be oft-discussed this offseason, but Matthews seems unsurprisingly aware and ready for the next step.

In an article from Rob Reischel for the Milwaukee Journal Sentinel, Matthews said of the expanded role: “I think it’s just the natural progression with leadership on this team. Obviously the more comfortable I am in the scheme, which I very much am, the longer I’m here, the more tenured I am, the more I have to take that leadership opportunity.”

Since their Super Bowl run, the Packers have been gashed for big, highlight reel plays and stacks of yards from time to time. They have battled injuries and inconsistencies, the defense is not the sole issue, but there’s little doubt that the unit needs to tighten up if Green Bay is the title contender it wants to be. Along with adding to his sack total, Matthews will be expected to showcase those unquantifiable virtues associated with leading a football team. The numbers are important, so too is reputation. The way last season ended, Green Bay’s defense has repairs to make in each. Matthews, the face of the defense, can mold it in his own likeness, much like the defenses led by Nitschke were molded to his gruff style.

‘It is time’

Ray Nitschke is the quintessential middle linebacker.

“He’s one of the best linebackers to play the middle in NFL history,” Murphy said. “If you talk to his opponents he was intimidating, he was hard-hitting. He left it all on the field.”

Nowadays, Matthews is the mold the NFL uses when looking for the next powerful pass-rusher that attacks from the outside.

“It’s such a different day and time. They’re both winners,” Murphy said of Matthews and Nitschke. “Clay, I’m sure he’s an excellent athlete, he takes great care of himself. Time will tell.”

Nitschke’s drive was fueled by violent passion. Matthews seems to enjoy the terror he inflicts on opponents like a bear playfully toying with a rainbow trout. Matthews enters a season where his opportunity to lead is as big as ever; Nitschke left the game as one of Green Bay’s greats in the category.

In short, Matthews is on a rare track. He started carving his own legacy in Green Bay in his rookie season and hasn’t stopped yet. Despite the different ways each approach linebacking, despite their varying skill sets and personalities, Matthews and Nitschke are more alike than they look at first glance. Nitschke was a prolific ballhawk, much like Matthews is today. Matthews plays more on the edge of the defense, but accumulates the paint-chipped helmet scars and tattered jerseys that’d probably make Nitschke grin a little. They’ll never be the same, yet their roles on, and importance to, their respective Packers teams are merging closer and closer together. As fans, we’re just lucky to have them both.

The audio and video footage of Matthews and Green Bay linebackers coach Kevin Greene on the sidelines before that game-changing forced fumble in Super Bowl XLV shows Greene — giving the exact sort of pep-talk you’d want and hope a Kevin Greene pep-talk sounds like — imploring the linebacker to make a play.

(*Quick aside: If you haven’t seen this in awhile, please watch it. The words are great but don’t do the feeling and intense Kevin Greene eyes justice.)

“Everybody looks up to Wood (Charles Woodson) as being a leader,” Greene said. “He’s gone. Nobody’s (expletive) standing up and (expletive) rallying the troops.

“It is time. It is time.”