Lined up across from guard Kraig Urbik in one-on-one drills, Dareus exploded out of his stance and lifted the 6-foot-5, 300-plus-pound offensive lineman off his feet before knocking him over - splat! - flat on his back.
''First day. Right here,'' Dareus said, a few days into this year's camp, pointing toward the spot where he made his disruptive debut some four years ago at the Bills facility on the St. John Fisher College campus.
''Around that time, I kind of felt a lot of people didn't know what I wanted to do, and what my goals were,'' he said. ''Today, I feel like I am who I was expecting.''
He's played up to the Bills' expectations as well.
Drafted third overall out of Alabama, the now 25-year-old has established himself as one of the league's top, young defensive lineman.
Dareus is coming off his most impactful season in which he led NFL defensive tackles with a career-best 10 sacks. And the two-time Pro Bowl selection is entering the final year of his contract, which puts him in a position to become one of the league's top-paid defensive linemen.
The Bills have already exchanged contract offers, and general manager Doug Whaley says he's confident a deal can be completed before the start of the season.
The timing of the deal matters little to Dareus, who notes the future will take care of itself. It helps that he's already being paid a base salary of just over $8 million after the Bills exercised their option to pick up the fifth year of his contract.
''Being totally honest with you, I'm not in a rush because I'm not in a pickle,'' Dareus said, referring to contract talks. ''Whatever happens, happens. If not, we'll talk about it when we get there.''
And yet, many can't help but talk about it, including Rex Ryan.
The Bills new coach and defensive specialist cracked a joke when beginning to answer a question of how impressed he's been with Dareus.
''I know he's trying for a new contract so no, not really,'' Ryan said, with a smile last weekend. ''I mean, you find these guys all the time with that kind of size, athleticism and all that. Yeah, they're a dime a dozen out there.''
But seriously, Ryan added, players such as Dareus are not common. He then referred to Dareus as having a ''unique skillset,'' because of how much power and speed he can generate with his 6-foot-3 and 331-pound frame - though he appears heavier.
It's also not lost on Ryan how integral a role Dareus will play as part of a formidable front-three rounded out by Kyle Williams and Mario Williams, with former defensive end Jerry Hughes expected to rush off the edge as a linebacker.
It's a foursome that returns intact for a third straight year, and has played a significant role in the Bills combining for an NFL-leading 111 sacks over the past two seasons.
Urbik has had a firsthand view of Dareus' development in practicing against him for the past five seasons.
''He's got that rare thing where he's 360 pounds, but he moves like he's 280,'' Urbik said.
Urbik noted Dareus has the power to bowl over a lineman or, if he chooses, the speed to blow past him.
In practice Wednesday, Dareus was facing two blockers when he grabbed backup guard William Campbell by the shoulders and simply pushed him aside.
Dareus said he's pinching himself over the opportunity to play in Ryan's aggressive system, and alongside his familiar teammates.
''We all know this is something special,'' Dareus said. ''It's playing backyard football. Whoever's got the ball, we're going to attack. It's just having fun.''
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