Let me introduce the Cincinnati Bengals defense to you this way: If you go back and calculate what each NFL team has allowed in points per game over their last 16 regular-season games, the best defense in the league has been that of the Seattle Seahawks, allowing a minuscule 14.8 points per game. They are often referred to as “one of the league’s best defenses,” if not “the best,” full stop. Just behind them, at 15.4 points per game, are the Bengals. It’s fair to say that the Cincinnati defense doesn’t get that sort of attention. I suspect that most people have some vague inkling in the back of their head that the Bengals defense is pretty good, but it deserves to be considered as one of the league’s two or three best units, alongside the Seahawks and Chiefs (third at 17.7 points per game).

It isn’t a points per game fluke, either; the Bengals led the league in defensive DVOA during the second half of the 2012 season and were fourth in the league this year, despite having played the Bears, Lions, Patriots, and Packers already through their first eight games. They force three-and-outs on 30.8 percent of their drives, second only to the Texans. They are a force of nature that no offense in football would want to face.

And yet they might have the most anonymous great defense in football. Their star player is a midround pick who devours double-teams and still manages to make plays in the backfield. Their secondary is pieced together from the jokes of other teams. Clay Matthews has more commercials during one break than this entire defense does; hell, Clay Matthews’s mom has more commercial action. More players from the Cincinnati offense (three) made the Pro Bowl than its defense (one) last year. The same thing will probably happen this year.

Take a look at how the Bengals have put together this defense and you begin to see how truly impressive the whole thing has been. The Bengals are not the Chiefs, a defense built on first-round picks and free agents. When they line up to play the Dolphins tonight, they won’t start a single first-round pick they drafted themselves on defense; the only homegrown first-rounder who will see snaps is cornerback Dre Kirkpatrick, who was buried on the depth chart until starter Leon Hall tore his Achilles again earlier this season. They will start a second-rounder, a third-rounder, two fourth-rounders, a fifth-rounder, and five guys they acquired at their absolute lowest possible value. They, more than anybody else, are the defensive equivalent to the castoffs of the Saints offense. There’s no Drew Brees here, but the closest thing is up front. To figure out how the Bengals got here, you have to start there.

The Front Four

When everybody’s healthy, Cincinnati has an eight-man rotation up front, and seven of those eight players are homegrown talents. The exception, Wallace Gilberry, is a supremely underrated situational pass-rusher. Each of the seven other players were drafted between the second and fourth rounds; the Bengals place a huge importance on drafting players for that front four, but they also have enough confidence in their ability to develop players into above-average contributors. They’re not quite yet a defensive lineman factory, but the plans for the building have been drawn up.

The star is defensive tackle Geno Atkins, who was apparently hiding from the attention of NFL scouts in college by attending Georgia. At the time of the draft, Atkins was seen as a productive-but-undersized defensive tackle who might be able to use his athleticism to get into the backfield and make plays. Somehow, Atkins fell to the fourth round of the 2010 draft. I don’t understand it, either. It was a good draft for defensive tackles, considering Ndamukong Suh and Gerald McCoy went with two of the first three picks, but Atkins was the 120th pick in the draft. Eight of the guys taken ahead of him in the fourth round alone are out of football.

It’s not that Atkins has somehow turned into a totally different player from the guy that the league saw in college. He’s still a 3-technique tackle, and at 303 pounds, he’s only 10 pounds heavier than the guy who was too small at the combine. The difference, now, is that Geno Atkins’s perceived weaknesses are strengths. Atkins’s size doesn’t make him too small to play on the inside; it makes him impossible to block. He’s too quick for guards to stop, and when they do get a hand on him, he’s more than capable of getting underneath them and using his leverage and brute strength to shove them away. That’s how this happens:

Mays included that image in his All-22 treatment of Atkins before the season. It’s mesmerizing. That’s one man basically running another over.

Atkins has sharpened and refined his game. He’s become an insatiable tape-watcher. His technique has improved. He’s stronger. The results have been extraordinary. Atkins showed flashes during his rookie year, but he’s turned into the league’s best interior lineman. Bill Belichick said that, looking back, he would have taken Atkins with the first pick of the 2010 draft, subtly tossing shade at Suh and McCoy in the process. He’s the poster boy for this Bengals defense.

Likewise, the Bengals have built the rest of this front four around athletes that they’ve molded into reliable football players. Michael Johnson was another Georgia product, this time from Tech, and a freak who attracted attention before the draft for his ability to possibly step in as a 4-3 defensive end or a 3-4 outside linebacker thanks to his 266-pound frame. Yet, on draft day in 2009, nobody was willing to pull the trigger; he fell all the way to the third round, where the Bengals took him with the 70th pick. Seven picks earlier, the Cardinals had used a second-rounder on defensive end Cody Brown; they would cut Brown before he ever played a game for the team.

The Bengals didn’t commit to Johnson at defensive end at first. They tried moving him to outside linebacker before 2010 and again in 2011 before settling on him as an end. Once he became the full-time starter at right end before the 2012 season, he broke out. Johnson had 11.5 sacks last year, and while he has only 1.5 sacks through seven games in 2013, he’s been an impact player as a run defender. That seems unlikely for a player who was supposed to shift to linebacker and purportedly flashed a lack of effort at times in Georgia, but again, the Bengals have gotten more out of Johnson than they would have expected.

It seems likely that the Bengals will move on from Johnson after this season, having franchised him a year ago while giving a long-term deal to the defensive end on the opposite side of the line, 2010 second-round pick Carlos Dunlap. Dunlap showed enough in a part-time role during his first three seasons that the Bengals gave him a $40 million contract after two professional starts. It helps when you pick up 20 sacks in 38 games, too. Dunlap’s another one of the defensive ends with long arms and another Bengals player who came out of school with complaints about his motor and effort. Again, he seems to be doing just fine at the professional level. Dunlap’s also just 24 years old, meaning that his best football could still be in front of him.

The player who stands out the most in the front four is probably Domata Peko. His notoriety comes from that massive mane of hair spilling out of his helmet and his occasional appearances at fullback on offense. Peko’s the veteran of the group, having come off the board in the fourth round of the 2006 draft. He didn’t have issues with his motor coming out of school, but was instead seen as overweight, with stamina issues. In addition to getting into shape, Peko needed to learn how to diagnose blocking schemes and get better leverage. Now, he’s one of the few defensive tackles in football capable of playing on all three downs without gassing out. At 29, he’s the elder statesman on a line full of young players. That’s a pretty impressive turnaround.

The Bengals back up that front four with Gilberry and three recent midround picks: 2013 second-rounder Margus Hunt (end) and 2012 second-rounder Devon Still and third-rounder Brandon Thompson (both tackles).

Notice one trend cycling through those four starters? They each got significantly better once they arrived in Cincinnati, with the weaknesses in their effort level or gaps in their production disappearing. Wonder how that’s happened.

The Back Seven

And now, for something completely different. All that homegrown talent and development is great, but the back seven is where the Bengals have made their — and this is weird to say — nose for a bargain shine. With middle linebacker Rey Maualuga missing Thursday’s game because of a sprained MCL, Cincinnati will start only one player in the back seven that it has drafted (2012 fifth-rounder George Iloka). The six other players are all projects the Bengals picked up at the absolute bottom of the market and turned into viable starters. No, really:

• Michael Boley, filling in for Maualuga while stepping in at outside linebacker, was a salary-cap castoff from the Giants this offseason who only signed with the Bengals on October 1. (Boley was also arrested on child-abuse charges in February.)
• James Harrison, who starts on the strong side, was signed away from the Steelers after he, too, became a salary-cap casualty. Harrison had spent his entire career in a 3-4 defense before moving to Cincinnati’s 4-3. He’s replacing Manny Lawson, who made the same sort of move when he came to Cincinnati from San Francisco.
• Terence Newman was run out of Dallas by mobs after years of declining play on an enormous contract, leading to his role as the scapegoat in Dallas’s 2011 collapse. (Hey, that sounds familiar.) Signed by the Bengals on a two-year deal for a total of $5 million, Newman has settled in as an above-average cornerback even though he’s 35. He nearly costs as much money on Dallas’s cap ($2 million in dead money) as he does on Cincinnati’s ($3 million).
• Adam Jones was another player sent packing by the Cowboys at the end of their Criminal Galacticos days. After spending the 2009 season out of football, Jones signed with the Bengals before the 2010 campaign and has slowly seen his role expand with the team; first a return man, Jones eventually saw more reps at cornerback and is now a full-time starter with Leon Hall out for the year. He has even stayed (relatively) clean off of the field; he was found not guilty on would-be assault charges from June, although he was arrested on a disorderly conduct charge in September. For what the Bengals have paid him — about $3.6 million over the past four seasons — they’ve gotten far more out.
• Reggie Nelson is one of the more underrated safeties in football and a classic buy-low victory for the Bengals. He was a first-round pick in the 2007 draft, taken by the Jaguars in the final draft before Gene Smith took over their front office. (He was merely director of college scouting for that one.) After three disappointing seasons, the Jaguars wanted to get rid of Nelson and traded him just before the beginning of the 2010 season to Cincinnati for cornerback David Jones, who was one of the worst players in football during his time on the field. And the Jaguars were so bad at safety that year that they traded for and then moved cornerback Dwight Lowery there, and gave Dawan Landry a $27 million contract the following offseason. Jaguars football! Nelson hasn’t made a Pro Bowl, but he’s been around that level over the past two seasons.

The final member of this defense is the Bengals development pattern in a nutshell. You’re probably familiar with the Vontaze Burfict story, but for the uninitiated, here we go. Burfict was penciled in as a first-round pick in mock drafts before his junior year in college, but had a wildly disappointing and erratic campaign before deciding to leave school early. He followed that with one of the worst combine and pre-draft stretches of any prospect in recent memory, with a slow 40-yard dash time, reports that he was out of shape, and even a failed drug test at the combine, which is downright incredible; that’s failing a drug test that you know is coming months in advance. (It’s also worth noting that the Bengals drafted Andre Smith, another player who had a famously bad combine run.) Burfict, the former presumptive first-round pick, the guy who was 12th on Mel Kiper’s Big Board before his final season at school, went undrafted. The Bengals signed Burfict by offering him the league minimum and a signing bonus of $1,000.

Since then, Burfict has become every bit of the player the mock drafts expected him to be. With Maualuga entrenched in the middle and weakside linebacker Thomas Howard suffering a torn ACL in practice after Week 1, Burfict stepped in and did an admirable job playing out of position. His role expanded with the team as the season went along, eventually becoming an every-down linebacker. This year, he’s played 96 percent of the defensive snaps and will become the team’s middle linebacker with Maualuga out. Burfict might not give the position back to Maualuga when he returns, either. The whispers about off-field mistakes and taking plays off have disappeared, too. The undrafted free agent who every team passed on is now the league’s leading tackler.

Midround picks becoming superstars and valuable contributors. Undrafted free agents with luster restored. Veterans with little value rehabilitated into above-average starters. How does that happen?

The Coaching Staff

Putting everything into perspective, it’s clear that a good amount of the credit for what the Bengals have been able to accomplish on defense has to go to their coaching staff, notably head coach Marvin Lewis and defensive coordinator Mike Zimmer. Who else could have turned this motley crew of low-motored, written-off mistakes into one of the league’s best defenses? Just as we don’t think of the Bengals as a great defense, Lewis and Zimmer rarely get attention as two of the better coaches in the league, but how can you argue against that moniker given what they’ve done with the defense? They’ve done phenomenal work.

It’s hard to imagine that what Cincinnati has done over its past full “season” is a fluke. The Bengals have lost Hall, their best cornerback, to a torn Achilles for the second time in three seasons, but would you bet against Lewis and Zimmer turning Kirkpatrick into a viable contributor at corner after his success at Alabama? And considering that the only above-average offenses they face over their final eight games are the Chargers and Colts, well, that points-per-game figure might even be dropping even further. With a comfortable lead in the AFC North and a rapidly improving quarterback, the Bengals aren’t going anywhere. The Cincinnati bandwagon is about to get very, very full.