This story appears in the Dec. 17-24, 2018, issue of Sports Illustrated. For more great storytelling and in-depth analysis, subscribe to the magazine—and get up to 94% off the cover price. Click here for more.

Mere weeks after the Rams' season had ended in a first-round playoff loss to the Falcons, and just days after he had accepted the 2017 NFL Defensive Player of the Year Award, Aaron Donald went back to work last February and came clean to his longtime personal trainer. "Him getting MVP, he told me he didn't deserve it," says Dewayne Brown. "He felt like he wasn't playing his best football yet."

Two months earlier, not long before the Pro Bowl teams were announced, a Rams media relations staffer had approached Donald to go over the interview schedule that would coincide with his fourth nomination in as many seasons. Donald interrupted her and asked, "You think I'll make it?"

Julia Faron laughed until she saw Donald's expression. "Oh, you're serious?" she said. "Yeah, I think you'll make it."

None of it surprised Brown, who has been working with the 27-year-old tackle since he was at Penn Hills High in Pittsburgh. "That's how he is," Brown says. "He's on some Kobe Bryant, Michael Jordan type stuff."

When they first started training, Donald was a pudgy junior who was just catching the workout bug. But soon he became obsessed. If the teenager who topped out at 6'1" couldn't become the prototypical hulking gap-stuffer, he figured he would be something ... different.

On his way to sweeping the Nagurski, Bednarik, Lombardi and Outland awards as a senior at Pitt, Donald morphed into a pass-rushing menace who showed up at Rams camp three years ago weighing 280 pounds, with less than 10% body fat. Even more cut now, he has 55½ sacks in 75 games—the most by any player to start his career—and, with three games left in 2018, he's six sacks shy of matching Michael Strahan's single-season record of 22½.

Kohjiro Kinno

Yet this son of a bus driver (that would be his mom) wonders if he's good enough to be a Pro Bowler or worthy of one of the NFL's highest honors. "You never know," Donald says, with no hint of irony. "There are a lot of good football players in the league. You just try to keep yourself grounded."

That mind-set is what makes great players fun to be around, says Wade Phillips, the veteran defensive coordinator who came to Los Angeles last season. "Guys with that ability and that drive, they all have the same tendencies," Phillips says. "They're not full of themselves. They don't think of themselves as the best and they're not satisfied."

Phillips, 71, is the envy of nearly every DC in the league. Ask any offensive-minded coach to name the most disruptive defenders—those who eliminate the biggest chunks of opponents' playbooks simply by being on the field—and Donald is always in the top two. "The obvious ones are [Broncos outside linebacker] Von Miller and Aaron Donald," says 49ers coach Kyle Shanahan. "You want to attack weaknesses, but players like that hide a lot of problems. Defenses can be a lot more aggressive in coverage because people are scared to attempt certain plays, because the odds of getting sacked are way too high."

Yet unlike his peers in the pass rushers' pantheon, Donald does his damage from the interior of the line.

Greg Nelson

When Phillips coached the Eagles from 1986 to '88, he moved Hall of Fame lineman Reggie White to the outside to utilize his speed and prevent him from getting swallowed up by double-teams on critical passing downs. Phillips did the same with the Texans' J.J. Watt from 2011 to '13. The edge is also where Miller and Khalil Mack, the Bears' linebacker, line up in order to create havoc. But Donald, Phillips says, "supersedes that theory that you need to move him outside. He cuts the corner so quick on a guard, like a defensive end would do, but with less space."

And he leaves a lasting impression. Talk to a guard who has played Donald, and he'll tell you he hasn't faced a similar challenge. "He can scratch his knees standing up, but he still has that natural pad level where he can lift you up and forklift you," says Denver's Connor McGovern. "You can't replicate it. There's nobody that's ever done it like him. He does this crazy move where he bull-rushes and then he literally jumps off the ground and sheds you."

Donald calls that move the "power pop," something he developed with former L.A. defensive line coach Mike Waufle. "Power to one side and pop off to the other side once you feel the weight switch," Donald says. "Me jumping up and pulling myself through is extra momentum I use to try to explode to the quarterback a little faster."

Aaron Donald Wins Sports Illustrated's Performer of the Year Award

There's one more thing Donald does, which no other defensive tackle even tries, much less replicates. When teams slide the protection his way, sending the center to help a guard block him, Donald will often sprint to the outside shoulder of the guard, disarm his hands with a slap, and bounce off the inside shoulder of the tackle on his way to the quarterback.

"He understands they're going to try to overset him and the center's coming with him," says Rams offensive lineman Rodger Saffold. "In order to beat that, he goes outside because a lot of guards have trouble blocking the outside when they double-team. To get upfield he uses the tackle as leverage to get back on his angle [to the quarterback]. And then, just when you think you need to set wide, he hits you with a bull-rush and now you're floating backward. Good luck."

John W. McDonough

Attempting unconventional moves requires freedom, which Donald has enjoyed since entering the league as the 13th pick in 2014. During OTAs as a rookie, Donald was watching film when his new position coach, Waufle, joined him for a one-on-one chat before a position-wide session. "He came in and said, 'I'm going to say a lot of things in this meeting but I don't want you to listen to anything I'm saying,'" Donald recalls. "'I just want to watch you play and learn from you. Go out there and fly around.'

"It was surprising. Most guys have to earn that," Donald says. "When you have your coach telling you that as a rookie, it gives you a lot of confidence, makes you feel comfortable. He wanted to see if what I did in college could translate."

It did.

With 18 tackles for loss, 13 quarterback hits and nine sacks, Donald was named Defensive Rookie of the Year. He kept working with Brown in the offseason, telling his trainer in moments of mid-workout anguish, "If this s--- didn't work, I wouldn't do it." He also began to understand how offensive lines call out their protection slides, and what's coming when they don't. That's why you'll see Donald crouching just before the snap, scanning the line and the backfield, the last player to put his hand down in the ready position.

He also started studying linemen on an individual basis, watching even more film on his off days. "I used to stay late and watch film and every time I'd walk in he'd be in there, last guy in the building," says Eagles defensive end Chris Long, a former teammate. Then Donald started studying backups to prepare to face them. "I could tell that he knew what my weaknesses were," McGovern admits.

Along the way Donald started thinking about bigger goals, beyond Pro Bowls and year-end awards. He's always wanted to win a Super Bowl, but now he wants a gold jacket too. "Yeah, I think about the Hall of Fame," Donald says. "I don't do all this training to be good. I want to be great, I want to be mentioned with the best to ever play the game."

Miller, a sack virtuoso in his own right, says that what Donald's done in five short seasons has already made him near peerless. "It's hate if I can't tell you the truth," Miller says. "He has the flame right now, and he's had it for a long time."