Darren Waller was in a fantasy football league once. Just once. Years ago, a friend of a friend needed one more person to fill out their league, so he gave it a try. His team had some big names, but ultimately, few of them produced. He finished second-to-last. Today, Darren Waller doesn't play fantasy. He gets drafted in it.

The 27-year-old Las Vegas Raiders tight end is a year removed from the best season of his career -- a breakout that saw him catch more passes in 2019 (90) than all but 10 NFL players and post more receiving yards (1,145) than all but one other player at his position. He's the Raiders' top pass target entering the new season, a favorite of quarterback Derek Carr. And he's widely considered a borderline top-five player at a spot occupied by stars like Travis Kelce, George Kittle and Zach Ertz.

Before all this, however, the real fantasy was thinking Waller would ever get to this point.

"When I was a teenager, I was a real sensitive kid," he tells CBS Sports. "I didn't really fit in much, and that kinda bothered me, so when I was 15, I started doing drugs and drinking and stuff. It was my way of kinda making friends and living out my emotions. I thought that drugs were just the recipe for me to get through the stress. I know I became addicted quickly."

HBO's "Hard Knocks" spotlighted this part of Waller's journey in the lead-up to his triumphant season, detailing his descent into everything from pills to marijuana to alcohol to cocaine during a failed stint with the Baltimore Ravens. This month, as he celebrates three years of sobriety, he's still carrying the story with him as a reminder of how things have changed.

"Somehow I still made it to the NFL, but not with really much confidence or self-respect," he recalls. "I had countless failed drug tests, didn't really have any relationships with guys on my team. But after I was suspended from the league, I was kinda able to step away from everything and stop putting on a mask."

All of the heartache and unmet expectations have since been overshadowed by Waller's sudden burst into NFL stardom.

"I never thought it'd be anything like this," he concedes, "that I would be considered at the top of my position group or anything like that. But we're here now."

And yet Waller himself hasn't just left his past behind, as if it never happened. He can't. He won't.

"To see so many people idolize these players that do amazing things on the field, sometimes we forget that we're human beings, too," he says. "I'm as far from perfect as anybody can possibly be ... But I just think those things -- rigorous honesty and humility -- have allowed me to be free from my past, in a way. I was working at a farmer's market for, like, seven months when I was out of the league, so I don't get too high or too low. I know what it's like to be somewhere I'm not being idolized or cheered for."

Make no mistake: Waller is working to elicit as many cheers as he can get in 2020. Rewarded with a four-year, nearly $30 million contract extension last November, he's intent on replicating his Pro Bowl-caliber production during the Raiders' first year in Vegas.

"I want to be consistent and available like I was last year," he says. "We've got a lot of new weapons, so if that takes my numbers down, then that's OK. But I don't wanna be a flash-in-the-pan guy, here one year and gone the next. I definitely expect big things."

He's got equally high hopes for the Raiders, who went 7-9 a year ago and play in the same AFC West that houses the defending Super Bowl champion Kansas City Chiefs.

"Derek Carr, he's stepping up his game; I don't think there's anyone that's worked harder than him this year, and it's not just a big year for him, it's a big year for all of us," Waller says. "For us, our goal is to win the division, and from there, we'll see what happens. We're going for that first. I feel like we can win the division and then go from there."

Most of all, though, Waller is thankful for the platform he has amid the football. He's seen plenty of other players whose careers were on "life support" because of their own issues, and most of them, he says, "don't make it back." 

So he relishes the prominent voice he can now give to those who might be dealing with their own demons -- especially those who don't have NFL-caliber talents to fall back on, those who could only dream of growing up to be an NFL tight end.

"When I was out of the league for a year, the league and their drug program allowed me to go to an outstanding treatment facility," Waller says. "The whole experience was amazing. I know, just from family members to people I grew up with, there are facilities like that that people don't have access to ... So being able to possibly offer that kind of experience to people, that would just be me paying it forward."

That's why, in launching The Darren Waller Foundation this August, he plans -- starting in 2022 -- to begin funding drug and alcohol treatment for families who can't afford it. The money will come straight from his own pockets.

Best-case scenario, it affords some other wayward young man a chance to turn things around. To find a life free from addiction. To make their fantasy a reality.