Mike Jones | USA TODAY

USA TODAY Sports

FOXBOROUGH, Mass. – Jay-Z’s “Can I Get A” broke out on the sound system set up around the New England Patriots’ practice fields behind Gillette Stadium just as Sunday morning’s calisthenics period commenced.

Bob DeChiara, USA TODAY Sports

Tom Brady had just stepped onto the field, but froze as soon as the music started.

Then the quarterback’s shoulders began to shimmy beneath his pads and red non-contact jersey. Back and forth, side to side, keeping with the beat of the 1998 rap hit.

“Can ya, can ya, can ya bounce wit me, bounce wit me,” Hova spat as Brady bobbed his head up and down, flashes of sunlight bouncing reflectively off of his silver helmet. After a moment, the quarterback fell in step with his teammates as they made their way to midfield and back, loosening up for Day 4 of training camp.

If you didn’t know any better, you would never guess that it’s Camp No. 19 for Brady – the only player on the roster born in the 70’s and just days away from his 41st birthday.

Brady is seven years older than the next-oldest Patriot, kicker Stephen Gostkowski. But he appears as youthful as ever.

“Nothing’s changed,” backup quarterback Brian Hoyer told USA TODAY Sports when asked to compare the Brady he met as a rookie in 2009 and the Brady that he knows today. “Just the gray hairs, I guess.”

Hoyer laughs.

He’s always slipping in these playful jabs to remind Brady of his age, because the future Hall of Famer refuses to acknowledge it himself. But truthfully, Hoyer – reunited with Brady last fall after stops in Arizona, Cleveland, Houston, Chicago and San Francisco – finds himself both amazed and motivated by his teammate and good friend.

If Brady’s physical decline has begun, it remains undetectable by the human eye. Mentally, he remains razor sharp. And his passion and competitive fire rages on.

Brady hates losing at anything – a regular-season game, last February’s Super Bowl versus Philadelphia, or even throwing drills. Every practice, he and Hoyer compete to see who has the quickest release and most accurate delivery.

“He can miss by this much,” Hoyer says holding his fingers a couple of inches apart, “and he’s furious. That’s refreshing for me, and to see that, it makes me want to be that way, too. ... He’s so meticulous and his work ethic, and the way he is in the drills. And considering everything that guy has accomplished and that he’s going to be 41 years old? It’s inspiring.”

The Patriots again have pinned their hopes on Brady as they enter the 2018 season. Throughout this 19-year, five-Super Bowl trophy Bill Belichick-led dynasty, players have come and gone. But Brady has remained the constant. This offseason saw the exit of four more franchise cornerstones – cornerback Malcolm Butler, left tackle Nate Solder, wide receiver Danny Amendola and running back Dion Lewis – but the Patriots remain favorites to win their division and conference because No. 12 remains at the helm.

Questions about the health of the franchise cropped up last season amidst rumors of division between Brady and Belichick over the quarterback’s personal trainer. And Brady’s absence during the voluntary portion of spring practices only fueled speculation that the coach-quarterback relationship had further deteriorated and put the team’s winning tradition at risk.

But Patriots players scoff at that. Belichick declines to dignify questions on the topic with even compound sentence answers. And Brady on Saturday maintained his cover boy smile and responded, “I have no thoughts,” when asked to weigh in on rumors of turmoil between the two.

The Patriots had the resources to move up in the draft and select one of the top quarterback prospects, but opted against doing so because of their confidence in Brady.

However, the team and quarterback truthfully find themselves in virtually uncharted territory. Because so few quarterbacks have managed to remain both healthy and effective beyond the age of 40, it’s hard to predict just how much longer Brady can keep this up.

A 40-year-old Brett Favre led the Vikings to a 12-4 record in 2009 before falling in the NFC championship game, and then went 5-8 as a 41-year-old. And Warren Moon in 1997 as a 41-year-old starter for the Seahawks went 7-7 and made the Pro Bowl, but at 42 in 1998, he battled injury and went 4-6.

“It was easy for me (to stay motivated) because I was still chasing that ring, but that’s where for me, that’s what’s most impressive about what Tom is doing,” Moon said in a phone interview with USA TODAY Sports. “He’s been in the Super Bowl eight times and has five rings, so what is his motivation to keep doing this? He really loves the competition. ... So, that’s just so impressive how he’s able to keep stacking on top of what he’s done.

“But another key is he’s been in the same system for his whole career and as you get older and know all the nuances, the game gets easier. ... And he takes care of his body and is a great studier. So, it’s all just really impressive.”

Brady last season remained on another level after turning 40. His 4,577 passing yards led the NFL in 2017. It would surprise no one within the Patriots organization if he did so again in 2018.

They continue to believe because Brady is part freak and part unmatchable in the preparation department. Sure, the TB12 Method has garnered some sideways glances, but it’s hard to argue with the results.

Last year, while still with the 49ers, Hoyer purchased Brady’s book to glean secrets that he could implement in his own diet and preparation. Although younger than Brady at 32 (33 in October), Hoyer does see improvements in how he feels thanks to the cleaner eating, and the training that’s focused on flexibility and lengthening muscles rather than bulk.

But, the mental approach carries equal importance, Hoyer says. Brady thirst for knowledge remains unquenchable, Hoyer says.

“That’s the thing about quarterback: you should keep learning,” he explains. “The more you see, the more you’re learning all the time. ... So, as long as you can sustain physically, and if you as a quarterback keep building up that library, you’ll just get better and better.”

Balance also ranks among the secrets to Brady’s continued success, Hoyer explained. Just as he has modified his approach to strength training, Brady has identified ways to maximize his time so he adequately prepares as a player, but still has time to devote to his family. Maintaining that healthy balance between work and family time factored largely into Brady’s decision to skip the voluntary portion of New England’s offseason program.

But now that the season’s work has returned, so too is a fully focused Brady, perfectly at peace with his approach to the offseason and completely energized while demanding just as much out of his teammates as he does himself in hopes of securing the sixth Super Bowl title that eluded him in February.

“You know, there’s a lot of commitment and a lot of sacrifice from a lot of people that play the game. Our families, you know, they work just as hard just like every working family shares the burden at different times,” Brady told reporters Saturday. “It’s a full-time commitment for this team, and everyone’s got to do whatever it takes to help us win. ... It’s never perfect. Hopefully there’s a lot more good than bad, but you just work it every day and try to do better each day.”

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