The hulking defensive lineman, selected third overall out of Alabama, signed a four-year, $20.4 million contract and arrived at training camp in time for the team's first conditioning session at training camp in suburban Rochester on Friday.
"Now I can talk to my godfather from a distance," Dareus said with a smile, referring to Lester Reason, who provided the player a place to stay in exchange for having his grass cut. "Now he doesn't have to kill me every morning."
Now it's coach Chan Gailey's turn to get Dareus up to speed on his pro career starting Saturday, when the team holds its first practice.
"It's great to just focus on football," Dareus added. "It's something that you worked your butt off for."
Terms of Dareus' contract were provided to the Associated Press by a person familiar with the deal, who added the entire contract is guaranteed. The person spoke on condition of anonymity because the Bills have not released terms.
Gailey was pleased with Dareus' arrival.
"For him to be in meetings now and hear everything that's being said and being in the walkthroughs tomorrow, that's huge to get that done," Gailey said. "He's a big strong fast young man that plays with a little bit of an edge to him. ... I think he's going to help us a lot."
The Bills also announced the signings of cornerback Aaron Williams, a second-round pick out of Texas; North Carolina defensive back Da'Norris Searcy, a fourth-round pick; and North Carolina running back Johnny White, a fifth-round pick.
Buffalo has now signed eight of its nine draft picks, with only LSU linebacker Kelvin Sheppard, a third-round pick, still unsigned.
Dareus is the team's key offseason addition. He's being counted upon to make an immediate impact to what was a porous defense last year in ranking last against the run and allowing an average 26.5 points a game during a 4-12 season.
Listed at 6-foot-3 and 308 pounds, Dareus is a versatile lineman, who proved capable during a three-year college career playing against the run and pressuring the quarterback. He's expected to play end when the Bills line up in a 3-4 scheme, and would play the middle when they go with a four-man front.
Dareus had 11 sacks and 20 quarterback pressures in 33 career games, including 15 starts. He was also part of a defense that finished in the top 10 in the nation against the run in each of the past two seasons. Most memorably, Dareus was the defensive MVP in helping the Crimson Tide defeat Texas in the 2010 national championship game.
Though unhappy with the developmental time he missed as a result of the NFL lockout, Dareus is confident he doesn't have much catching up to do.
Dareus said he spent time with Bills safety George Wilson learning the team's defensive philosophy.
"Surprisingly, no. I don't feel like I'm behind at all," he said. "For the most part, I'm just ready to go."
One of the last players out of the locker room before the conditioning session began, Dareus jogged out on to the field and caught up to veteran linebackers Andra Davis and Reggie Torbor. He grabbed Davis by his shoulders from behind to say, "Hello," and then body-bumped Torbor.
Signing his contract was a meaningful moment for someone who grew up relatively poor in Alabama.
"Phew, man," Dareus said. "Finally made it. The draft came along, the combine, all the workouts, they were all worth it. It paid off to this point where I can sit down and sign my name, and it's all mine."
Dareus doesn't plan any big spending spree.
"Invest it well and do the best you can with it," he said. "I don't want to go back from where I came from."
And he's not preparing to give up on his grass-cutting gig come the offseason.
"I'll be excited to get back home," Dareus said. "I promise you, my godfather is going to have the grass uncut on purpose so I can get it done."
Williams, drafted 34th overall, had 106 tackles, three sacks and four interceptions in 37 games, including 23 starts, at Texas. He led the Longhorns with 13 passes defended last season.
Searcy, selected 100th overall, had 106 tackles and five interceptions in 48 career games, including 23 starts with the Tar Heels.
White, selected 133rd overall, led North Carolina with 720 yards rushing and seven touchdowns last year. He's expected to compete for a backup spot behind returning players Fred Jackson and C.J. Spiller.