LOS ANGELES -- Leonard Williams crouched slowly, placing his left hand on the artificial turf and glaring straight ahead. Across from him stood "ESPN Sport Science" host John Brenkus, dwarfed by the 6-foot-5, 300-pound defensive end. As Brenkus settled into his own three-point stance just inches away from Williams, an assortment of production crew members armed with cameras and microphones hustled to position themselves for the shot of these two men colliding. They knew what was coming -- Brenkus had tried to see how far defensive tackle Ndamukong Suh could throw him when Suh was entering the 2010 NFL draft -- but this current stunt somehow looked even more troubling.

After a quick countdown, Brenkus lurched forward and thrust his hands into Williams' chest. Williams did the same, only with frightening force -- extending his long arms, exploding out of his stance, surging the momentum through his thick torso and into Brenkus' comparatively spindly frame. By the time Brenkus landed some 6 feet away on thick, oversized padding, a mixture of gasps and laughter filled the studio as he lay motionless for a few seconds. "That," Brenkus said while still sprawled across the mat, "had to be some kind of new record."

It was good TV to see the host launched through the air by a man considered by many to be the best prospect in this year's NFL draft. It was even more appropriate that Williams paused for a second after the feat before raising his arms to flex his biceps. But what really made this moment so intriguing was that it was merely a small sampling of what Williams can do with a devastating combination of power, strength and explosiveness that has scouts all over the league salivating. In other words, this USC All-American can make plenty of opponents look as silly as Brenkus did during that shoot.

As much as people talk about the two high-profile quarterbacks in this year's draft -- Florida State's Jameis Winston and Oregon's Marcus Mariota -- the reality is that Williams is the player most often viewed as the surest thing for a team trying to improve its fortunes.

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"From the previous years, sometimes it's like taking a chance when you take a quarterback -- you never know what you're going to get," Williams said. "I'm going to bring that disruption and physicalness. And I'm going to get to the quarterback."

The consensus so far is that Williams isn't likely to slip beyond the top five picks when the draft begins April 30. He can dominate as a pass-rusher or a run-stopper, and his versatility makes him even more valuable to whomever drafts him. The ideal spot for Williams is as a defensive end in a 3-4 front, but he's strong enough to move inside as a defensive tackle in a 4-3 scheme. Since USC went through so much transition during his three years there -- he played for three different defensive coordinators in that span -- he's comfortable lining up just about anywhere. As USC defensive line coach Chris Wilson said, "Leonard didn't have a position here because we always moved him around to find the best matchup."

"When you think of a 3-4 defense, typically, you think of a big, two-gap player," said Tennessee Titans general manager Ruston Webster, who may have the opportunity to grab Williams with the second overall pick. "[It's] rare to find players that can do that -- play one gap, penetrate and get up the field and rush the passer. ... When you have a guy like Leonard who can do both, that's something special."

Williams' appeal also has plenty to do with his mental makeup. He's so loyal that he once told Trojans assistant coach Keynodo Hudson that he lamented leaving school because he would miss his teammates, he never beat UCLA and the program didn't regain its dominant stature during his tenure. He's also so humble that a little girl once kept him beaming for days simply by asking for his autograph when he was a junior at Daytona Beach Mainland High in Florida. At 20 years old, Williams also has a mix of intelligence and maturity after traveling a hard road to the level at which he now finds himself.

Even when Williams first heard his name mentioned among the best in the nation, he didn't allow his ego to swell. He was sitting in USC's McKay Center waiting for a team meeting during his sophomore year when somebody heard a "SportsCenter" report calling him the second-best NFL prospect in the country. "It didn't really affect me," Williams said. "I've never been the kind of guy who gets into being hyped up."

Added Hudson, who was Williams' defensive coordinator in high school: "If you have a conversation with Leonard, you'd never know he's been through all the things he's dealt with in his life."

Almost from the moment Williams was able to walk and talk, Aviva Russek sensed something unique about the third of the five children she shared with her husband, Clenon Williams. Whenever possible, she told Leonard he was special, that big things awaited him in the future. "He always had a humble soul," Russek said. "He was always open-minded and optimistic about life, and he never caused a problem in school. Sometimes, it's crazy to see how aggressive he is on the field because he's not that way in real life."

Williams first learned the game by hanging out with Clenon, who loved to spend his Sunday afternoons watching NFL action on his living room sofa. But when it came time for Williams to sign up for a local Pop Warner league as a seventh-grader, he received some jarring news: At 210 pounds, he exceeded the 180-pound weight limit. Williams cried instantly after hearing the rule. Even with reassurances from the adults around him -- a coach told him to keep the same passion that led to those tears -- Williams still felt like he'd done something wrong.

USC's Leonard Williams is arguably the draft's top talent and the potential No. 2 overall pick. Winslow Townson/Getty Images

"I was so excited to play because I'd been told by my parents that I could do it in the seventh grade," Williams said. "But when I found out I was too big, I started to get really insecure about being big. My dad eventually told me that someday my size would pay off."

That setback would turn out to be one of the least challenging of Williams' childhood. Far more troubling was the deterioration of his father, who programmed computers as a machinist but also struggled with drug addiction. Clenon often disappeared from the family for long stretches. Those absences left Russek, a nurse, with the task of raising her children on a limited income and few resources. In order to cope, she moved her family around the country to find better opportunities.

Williams was born in Bakersfield, California, but lived in Sacramento, California; Michigan and Arizona before he ever finished grade school. One of the low points for Russek came shortly before she left Bakersfield, when she moved her kids into a homeless shelter for a couple of weeks. She was forced to make that drastic decision because she had been housing her family in a hotel until the local school district said she needed to find a place it would accept as a legitimate address.

Russek said Williams probably gained some valuable wisdom during that time -- "He learned to not give up and to be strong," she said -- but the biggest test for her son came when Clenon was arrested and later sentenced to the Marion Work Camp in Lowell, Florida, for robbery with a dangerous weapon (he is due to be released on Oct. 2, 2019). Williams was a 14-year-old freshman at the time, a kid who finally had a chance to play football after entering high school. "My dad had his problems," Williams said. "He disappeared every once in a while, and then, one day, he just disappeared and never came back. It was really sad because we were really close. ... I never asked him what he did. I just knew he would be in there for a long time."

"If you have a conversation with Leonard, you'd never know he's been through all the things he's dealt with in his life." USC assistant coach Keynodo Hudson

"I think Leonard compensated for his dad's issues by focusing on football," Russek said. "He just put all his energy into that. He would tell me that he missed his father, but I would just say that sometimes people have to be removed from your life so you can do what you have to do."

Williams never let his father's troubles derail his dreams, because the rest of his family was too committed to seeing him reach his goals. His oldest brother, Nate, forbade Leonard from engaging in dangerous activities that they all once enjoyed -- such as riding dirt bikes or performing stunts on skateboards -- simply because it wasn't worth the risk. Williams' mother made sure she didn't let anything get by her. When she learned Leonard had been playing rugby with a nearby college club team -- he took up the sport when he couldn't play football in the seventh grade -- she decided to finally attend one of his games during his junior year. The minute she saw her son crashing into older players, her jaw dropped and her temper erupted.

"I went off when I saw him out there doing that," she said. "He was a teenager, and he was playing against grown men in their 30s. I told them I didn't sign any permission slips for him to do that."

Williams' high school coaches echoed the same sentiment. Blessed with quickness and naturally soft hands, he often inspired a fight between offensive coaches, who viewed him as a tight end, and defensive coaches, who wanted him on the line. Lacking the money to attend many college camps in the summer, Williams was heavily recruited by only Florida and Alabama prior to his senior year. The only reason USC heard about him was because Hudson raised the money to take Williams and two other teammates to a Trojans summer camp before Williams' senior year.

Williams was a menace to opposing QBs, compiling 21 sacks over three seasons. Jonathan Daniel/Getty Images

Even Williams' family didn't know he was going to USC until national signing day. When Aviva walked onto the stage for Leonard's big announcement, she expected to see three hats in front of her son -- USC, Florida and Alabama, the school Leonard had worshiped for years. Instead, she only saw the Crimson Tide and Trojans represented. "[Former USC defensive coordinator] Monte Kiffin came to Florida to recruit me," Williams said. "And he convinced me that it would be fun to come to the West Coast."

Williams became a star from the moment he joined the USC program. He started as a defensive tackle in his first season, piling up 64 tackles, eight sacks and an interception to earn Pac-12 freshman of the year honors. He was even better as a defensive end during his sophomore and junior seasons, tallying 154 total tackles and 13 sacks to twice garner All-America recognition. When the Trojans selected their team MVP after last season, Williams was the obvious choice for the award.

It wasn't just the numbers that set him apart from his teammates. It was the attitude he brought to the field every day. "Leonard has all the talent, but what makes him different is the investment he makes in the game," Wilson said. "He's great in the locker room. He's a great teammate and he loves to compete."

As much as Williams grappled with his decision to leave school early, he knows it's ultimately the best decision for him. He wants to ease the financial burden Aviva has coped with for years. He also has a 2-year-old daughter, Leana, back in Florida. There's also been subtle pressure from Nate and uncle Rock Russek, whom Leonard lived with in 11th and 12th grade. Both have long waited for a family member to get the kind of opportunity that eluded them. (Nate lost his shot at playing small-college basketball when he sustained a severe knee injury in a dirt-bike accident, while Rock's responsibilities as a young father ended his chances of landing a football scholarship.)

All of them will be watching the big kid with the quick smile and wild hair as he walks to the podium to greet commissioner Roger Goodell on April 30. Williams has been so focused on that moment that he wouldn't entertain media requests until he finished training for February's scouting combine. As he sat in a folding chair in between takes at the "Sport Science" studio, while frequently adjusting to an uncomfortable body suit lined with sensors, he seemed pleased with that strategy. Back then, his priority was ensuring that his stock didn't drop. Now, it's about enjoying the moment as he lets everybody see what he can become at the next level.

"It really doesn't matter where I end up being picked," Williams said. "I'd like to go in the top five, but at the end of the day, I'll be grateful regardless of where I end up."