MIAMI GARDENS, Fla. — During quiet moments on the sideline, Calais Campbell can still hear his father’s voice.

Truth is, it never left him. The words were stored away, hardened into his psyche. Charles Campbell saw his son’s path before his son ever could. Twenty years later, the lessons have lasted.

Like the time Calais — long, lean and consumed by football from the minute he first slipped on a helmet — bragged about two first-quarter sacks on the way home from a high school game. He felt on top of the world. Wait until his older brothers heard …

“What’d you do the rest of the game?” Charles asked, quieting the car. “You got satisfied.”

Or the time Calais climbed the steps of the high dive at the local pool, then froze once he got there, too terrified to jump. This ain’t gonna work, he told himself. He tried to beg his way back down, but dad wouldn’t hear it. “Once you start something,” Charles told his son, “then you finish it.” So Calais gritted his teeth and tiptoed toward the edge.

“Belly-flopped,” he says now, laughing. “Hurt so bad. But after that I jumped in 25 times.”

Charles had been gone four years by the time his son entered the 2008 NFL Draft. Calais left the University of Miami a year early, showed up to the scouting combine out of shape and figured he’d coast on his God-given ability. He was wrong. He bombed.

Teams wrote him off.

So he sat there that afternoon and seethed, watching helplessly as he tumbled out of the first round. He knew what his father would tell him: “You let everybody pat you on the back, and you didn’t put in the work. It’s always about the work.”

Calais had to wait 50 picks to hear his name called. He’s never forgotten.

“You know how many defensive linemen went ahead of me?” he asks. “Ten.”

Most of them didn’t last five seasons. He’s in Year 17.

He’s been playing so long that he once shared a high school field with his head coach.

It was 2001. Mike McDaniel was a scrawny wide receiver at Smoky Hill High School, just outside of Denver, on his way to Yale. Campbell was the best player in the state of Colorado, a 6-foot-8 game-wrecker with offers from every top program in the country.

“I still have a ribcage, so he didn’t tackle me,” McDaniel joked last month. “I stayed away from him. I was trying to coach here 20 years later. I couldn’t do that if I was dead.”

A month ago, Campbell’s agent called. The trade deadline was nearing. Six teams had reached out to the Dolphins, wanting to deal for the veteran defensive tackle. Among them was Baltimore, where Campbell played from 2020-22. The offer was a fifth-round pick. Another team — Campbell won’t say who — offered a fourth as long as a late-rounder was going back to them.

“A fourth?” Campbell says, flattered. “I’m 38 years old!”

But the Ravens made the most sense. Campbell was going to get another shot at a ring — maybe his last shot. The trade was all but agreed to. Then his phone buzzed.

“I can’t do it,” McDaniel told him. “You’re too valuable to us.” The Dolphins coach had nixed the deal. Campbell would stay.

At that point, the season looked lost. Miami was 2-6, tied for the second-worst record in the league. A gilded career would sputter to a forgettable finish.

A few nights later, standing on the sideline before kickoff of a “Monday Night Football” game against the Rams, Campbell heard his father speak to him.

Once you start something …

“That’s when I decided I was gonna do everything in my power to get this thing going,” he says.

Miami is 4-1 since.

Campbell’s 109.5 career sacks place him third among active players, behind only Von Miller and Cam Jordan. (Ronald Martinez / Getty Images)

McDaniel refers to Campbell as “the Tom Brady of defensive linemen.” Dolphins tight end Jonnu Smith calls him “the LeBron James of the NFL” because of the respect he garners around the league.

“One of my favorite teammates I’ve had on any team on any level,” Smith says.

Defensive end Zach Sieler admits there’s a running joke inside the position room: with Campbell on the roster, the unit’s average age is 33; without him, it dips to 27. “I’m so grateful I get to come to work every day with that guy,” Sieler says. “I’m always asking him, ‘What’s the secret? How are you still doing this?’”

Campbell never wanted to do anything else. He’s bounced from Arizona to Jacksonville to Baltimore to Atlanta to Miami. He’s played every position along the defensive line. He’ll step in on special teams and block for field goal attempts.

“He’ll do anything,” says one of his former coaches, Bruce Arians. “He’s more than just a run-stopper. He’s so rushable. He’ll blow up plays in the backfield. And the best thing he does is use those long arms to bat balls down and tip passes. We got so many interceptions off that.”

Campbell’s missed fewer games (15) than seasons played (17). He’s one of four defensive linemen in league history to make 250 career starts. He’s two years older than every defensive player in the league. Heck, he’s two years older than his own position coach.

He’s wrestled with retirement each of the last few years, dreading the prospect of getting his body ready for another season. It’s the first two weeks he hates the most. “Do I really wanna go through that torture?” he’ll ask himself.

But he hasn’t been able to convince himself to walk away. Not yet.

“The man could be at home sipping his Piña Coladas with his gold jacket on. Instead he’s putting everything he’s got into this team,” Smith says, shaking his head. “And you know the crazy part? He’s still one of the best players in the league at his position.”

Smith’s right. Campbell’s 27 solo tackles are fifth-most in the league among defensive tackles. His five batted passes are second-most. He’s second on the Dolphins in both sacks and tackles for loss, trailing only Sieler.

Consider for a moment how long Campbell has been at this: He was a rookie on the Cardinals team that made it to Super Bowl XLIII in February 2009. Kurt Warner was Arizona’s quarterback. He’s been retired for 15 years.

Campbell can still remember Adrian Wilson pulling him aside before kickoff that night in Tampa, begging him to soak in the moment. “Don’t take this for granted,” the veteran safety told him. “Getting here is hard.”

Campbell’s never made it back. “My No. 1 motivation,” he calls it.

Each spring, while he weighs his future, friends and family throw out an obvious question: “Why don’t you just sign with the Chiefs?” Campbell bristles at the idea. To him, it feels like a shortcut. He doesn’t want a free ride to a championship. He wants to be a reason his team hoists the trophy.

That drive was first fueled by doubt, from a father who taught him to run from complacency and from a high school basketball coach who told him he was picking the wrong sport. “You’re too skinny!” Campbell remembers hearing. “You could make it to the NBA!”

And from Arians, his second coach in Arizona, who once said something in a news conference that Campbell never forgot. “For a guy as talented as he is,” Arians told reporters, “Calais disappears too much.”

The comment made its way back to him. Family members figured he’d fume. “Aren’t you pissed?” they kept asking. Campbell shook his head, then stored the words away.

“From that day on I decided I was gonna show up in every ball game. Every … single … one,” he says, pounding the table in front of him. “B.A. knew how to motivate. B.A. made me a better player.”

Campbell spent the first nine years of his career in Arizona, where he earned Pro Bowl and All-Pro honors from 2014-16. (Christian Petersen / Getty Images)

Arians’ words lit a fire, and as Campbell’s career took off, so did his ambitions. At one point he decided to Google “Hall of Fame defensive linemen.” He spent hours poring over their careers, watching highlights, studying stats. He pictured his own path to Canton. What would it take? How long would he have to play?

Between 13 and 17 seasons, he decided. Fifteen seemed like a good number. He wrote it down. “Then eight years in, I told myself no way,” he admits.

More research. More conversations. Campbell picked the brain of Dwight Freeney, who played until he was 37. Then James Harrison, who played until 39. Then Bruce Smith, who lasted until 40. He started seeing the chiropractor every week. He added acupuncture and massages to his routine. He spent nearly $30,000 on his own hyperbaric chamber.

He fought off Father Time.

He was 10 years into his career but started to feel like he was in his 20s again.

“I might just do this until the wheels fall off,” he told himself.

Campbell leans back in his chair, letting the silence linger for a few moments.

He’s a mountain of a man, with the voice of a preacher and a smile that warms the room. It’s late November. He’s sitting inside the Dolphins practice facility, weighing the most trying moments of his adolescence against the Hall of Fame-worthy career that followed.

Does one happen without the other?

He’s thinking.

He grew up one of eight, too busy trying to keep up with his older brothers to notice the hard times sneaking up on them. At one point, when Calais was in junior high, the family was forced to spend six months in a homeless shelter, crammed into a room with metal bunk beds pushed against the wall. The boys would take multiple city buses just to get to school each morning.

For years Campbell bottled up the experience, never mentioning it in interviews. He wanted to keep the pain private. But it was always there, same as the words his father left him.

Liver cancer stole Charles Campbell away at age 61, five months before Calais’ high school graduation. His father never saw him suit up at the U. Never saw him play a down in the NFL.

“To tell you the truth, I don’t think my career’s the same without everything I been though,” Campbell says. “We’re all a product of our environment, right? I know I am. I had an incredible father who saw something in me. He pushed me, he motivated me, and all those situations helped build up this callus, this toughness in me. He’s still pushing me.

“That’s such an important part of my story.”

The story since: 17 NFL seasons, six Pro Bowls, a spot on the 2010s All-Decades team and the 2019 Walter Payton Man of the Year award. The foundation Campbell was honored for, the one he started way back in 2013, is called CRC. It’s named after Charles Campbell, whose son is now one of the most revered players in the sport.

Campbell won the NFL’s Walter Payton Man of the Year award in 2020 for a mixture of on-field performance and community service. (Tom Pennington / Getty Images)

Even so, after he arrived in Miami, Dolphins coaches weren’t sure how much he had left. Campbell didn’t sign with the team until June. He wasn’t there for a single offseason workout.

Then, a week into training camp, they put the pads on, and No. 93 started blowing plays up.

Austin Clark, Miami’s defensive line coach, began to envision Campbell lining up next to Sieler, a 29-year-old coming off his first 10-sack season. “Oh man,” Clark told himself, “we got a shot here.”

Five weeks after his first practice Campbell was voted team captain. One snap into the season he had his first sack. In the months since he’s transformed the unit, the defense and the building. After workouts, he stays on the field and tutors the Dolphins’ young pass rushers. In film sessions, he points out their mental mistakes.

“You can’t go through the motions around him,” McDaniel says. “First of all, he’ll call you out. Second of all, you’ll feel too guilty.”

On Saturday nights, the coach asks Campbell to address the entire team. “When Calais speaks, it’s just different,” Smith says.

Arians says it started in Arizona. Younger players would gravitate toward Campbell. He’d mentor. He’d motivate. He’d counsel. “A special player and a special leader,” Arians says. “One of the most positive guys I’ve ever been around in all my years coaching.”

It carried over to Jacksonville, then Baltimore. In 2022, Ravens defensive tackle Nnamdi Madubuike was two years into his career and fed up: he had just three sacks in 25 games. He was frustrated and losing faith. “Come visit me in Arizona this spring,” Campbell told him. So Madubuike did.

“I believed in my heart that I could be a guy who could really be a problem in this league and Calais was giving me insight that, ‘You are,’” Madubuike says. “When we don’t get the results we want in any field, you can automatically get discouraged. He always told (me) just to stay up, just stay focused, stay working and eventually you’re going to break through.”

Madubuike had 18.5 sacks over the next two seasons, made his first Pro Bowl and signed a four-year, $98 million extension with the Ravens last spring.

“I’m telling you, wherever I’m coaching the rest of my career, (Campbell) is gonna be around,” Clark adds. “If he doesn’t wanna coach, then I’m begging him to come by the building at least once a week. He has that big of an influence on guys.”

Campbell’s approach then is his approach now: “No. 1, be authentic with everyone,” he says. “No. 2, be the best version of myself. No. 3, love on people.

“If I do all of that, we’re gonna be all right. I believe that.”

The Dolphins are two games back of the final AFC playoff spot with four to go. Campbell’s pep talk to himself before the Rams game sparked something — starting that night, Miami ripped off three straight wins. Then on Sunday, they rallied to beat the Jets in overtime. A season that looked lost in early November suddenly has new life.

“We need nine wins,” Campbell keeps telling himself. “We get to nine wins, we got a shot.”

In the back of his mind, he knows this might be his last stand, the final chapter of a career born of drive and draft-day disappointment. If it is, it’ll end the way it started, with his father’s words ringing in his ears.

Once you start something …

(Illustration: Demetrius Robinson / The Athletic; photos: Todd Rosenberg, Andy Lyons / Getty Images)