He is, somehow, the longest-tenured Vikings receiver, the standard-bearer dispensing advice to the team's younger wideouts from his seven seasons in the NFL.

It's been a long time since Adam Thielen was the Division II kid trying to elbow his way onto the roster; only Kyle Rudolph and Harrison Smith have been with the Vikings longer, and a week from Saturday, at the end of the Vikings' first full week of padded practices, Thielen will celebrate his 30th birthday.

The two-time Pro Bowl selection is the focal point of the Vikings' receiver group now that Stefon Diggs is in Buffalo. Thielen squeezed in a few days of workouts with Justin Jefferson at Woodbury High School when the rookie receiver was in town this summer, and he is prepared to mentor the first-round pick the Vikings hope can replace Diggs as Thielen's partner.

No matter how established Thielen is, there's a dose of the old fighting spirit, which got him through his first years in the league, that never really leaves the Detroit Lakes, Minn., native.

Working with the Vikings' youngest receivers isn't the only thing that could spark it this season; For the first time in a while, Thielen might be in need of a bit of a bounce-back.

"I've had so much fun these past couple of weeks being around them," he said. "I'm looking forward to seeing these guys compete and trying to prove that I can still do it as well."

'Focus on my body'

Thielen used the NFL's extended offseason to rework his diet around clean sources of protein and redouble his efforts with longtime trainer Ryan Englebert, after a season in which he caught just 30 passes while missing most of seven games with a hamstring injury. Before last year, no injury — not even broken bones in his back before the NFC Championship Game in 2018 — had kept Thielen out of a game in his career.

"For me, it was to focus on my body, my nutrition, getting after it and training to become a better athlete [this offseason]," he said. "I really think when everybody does that and focuses on those things, you come back together and you're already a better team, before you've even stepped on the practice field."

His improbable rise from rookie camp tryout to All-Pro status, told hundreds of times by this point, has been a steady ascent from the moment Thielen bumped Nicholas Edwards from the Vikings' 90-man roster in May 2013. He won a practice squad spot with a spirited training camp performance at his alma mater, Minnesota State Mankato, and repeated it the next year to make the Vikings' 53-man roster. He scored his first NFL touchdown on a blocked punt return in 2014 and fashioned a five-year run — from that season through 2018 — in which he caught more passes and posted more yards than he did the year before.

The Vikings gave Thielen a four-year, $64.8 million extension in April 2019 that made him one of the NFL's 10 highest-paid receivers and put his average annual salary just above that of Diggs. Then the season's first two months brought cold splashes of adversity.

Thielen spoke plainly in the Soldier Field locker room about his frustration with the Vikings' lack of passing production after a 16-6 loss to the Bears, stirring up a coterie of national talk-show hosts who debated whether the receiver had called out quarterback Kirk Cousins and prompting Cousins to apologize for missing Thielen downfield while the two appeared on Cousins' radio show after the game.

That same week, Diggs missed two days of practices and meetings, incurring more than $200,000 of fines. His absence, sources told the Star Tribune at the time, was related to his own misgivings about the Vikings offense and his role in it, including the notion that Thielen enjoyed top billing over Diggs.

A lost season and partner

Cousins found Thielen for four touchdowns in the Vikings' next three games. But the fourth score — a 25-yard post route in Detroit — spurred the hamstring injury that would linger for nearly two months, through setbacks when the Vikings tried to get Thielen back on the field Nov. 3 in Kansas City and for a chilly outdoor practice following their Nov. 24 bye.

After catching three passes in his final two regular-season games, Thielen returned in force with 129 receiving yards and a 43-yard overtime catch to set up the winning score in the Vikings' wild-card playoff victory over the Saints.

But the Vikings lost 27-10 to San Francisco in the divisional playoffs, and Diggs was traded March 16, leaving Thielen without his friend and partner in the offense.

"It's different not having [Diggs] here, but we have a great group of guys and I'm looking forward to continuing to work with them," Thielen said.

His contract carries a $13.5 million cap hit and no guaranteed money in 2021; with the Vikings possibly facing a tight cap situation next year, Thielen could need a big season to keep his deal intact.

For that, he will lean on his tenacity and try to pass a bit of it along.

"I want to help everybody become the best player they can be, and if they want to use me as a resource, I'm here," he said. "They all know that. I love this game of football and I love to teach it and to use what I've learned to share with these young guys."