SEATTLE — Marshawn Lynch arrived at the start of the Seattle Seahawks' greatest decade. It was no coincidence. The Pete Carroll era would have neither a championship nor an identity without the running back turning every carry into an all-out brawl.

Of all the stars and eccentric characters who made the Seahawks as colorful as they were successful, Lynch was the galvanizing force. His powerful style, unrelenting toughness and mercurial personality defined the team during its memorable run. For six seasons in Seattle, Lynch was a handful — sometimes for his own franchise, always for the opponent.

So at the end of this decade, there is something poetic about the Seahawks, down three running backs and desperate for assistance, turning to Lynch again.

Even as they try to reinvent themselves as a championship team, they need a little “Beast Mode.”

It has been four years since Lynch left Seattle. He has retired twice, played for his hometown Oakland Raiders, goofed off around the world and even tried to light a blunt using the Al Davis memorial torch at Oakland Coliseum. Meanwhile, the Seahawks have torn apart and rebuilt their roster without suffering a losing season.

But without Lynch, they haven’t come as close to true championship contention as they are now. Injured and losing steam, they need a boost. If it were any other 33-year-old running back coming off the street and to the rescue, there would be rampant pessimism in the Pacific Northwest. But the return of Lynch? No matter how improbable, he makes the fan base dream the biggest dreams.

“Happy holidays,” the quote-stingy Lynch said Tuesday during his version of a news conference to reintroduce himself. “Merry new year. Y’all have a great day. It’s a great feeling to be back. Thank you.”

And then he walked away.

You’ll hear from him next on Sunday night when he tries to help the Seahawks win the NFC West in a colossal regular season finale against San Francisco. With a victory and some help, the Seahawks (11-4) could still end up with a postseason bye or even the No. 1 seed and home-field advantage throughout the NFC playoffs. But they’re limping to the finish because of injuries. This is a good time for Lynch’s swagger and fearlessness to enter the locker room.

“I mean, I’m not going to try to kid you that I didn’t understand that there’s going to be a little juice about that,” Carroll told reporters when asked about Lynch’s energizing presence. “It’s awesome. I don’t have a problem with it. I’m not quite sure what the result of all that will be, but it’s fun. It’s fun stuff. He’s been a great character.”

To maximize the present, the Seahawks need a dose of the past. Whatever Lynch can give, they’ll take. Travis Homer is expected to start and handle the bulk of the carries, but Lynch figures to get an opportunity. So will Robert Turbin, Lynch’s former backup, who was another emergency signing to combat the running back crisis.

It’s reasonable to expect very little, given that Lynch hasn’t played since October 2018. That didn’t stop Carroll from playfully hoping that Lynch could run for 110 yards against the 49ers.

If you were lucky enough to experience his first stint in the Pacific Northwest, you cannot explain the legend of Lynch without laughing. You just can’t. His exploits from 2010 to 2015 seem like tall tales yetwere so preposterously real.

There was the famous run that caused an earthquake. There were the Skittles he chomped during games — his mother, Delisa, called them his “power pills” when he was little — which led to CenturyLink Field fans showering him with the rainbow candy after touchdowns. There was the time, on a 20-degree day in Kansas City, that he stayed on the sideline during halftime because he claimed his back hurt too much to move.

The laughter wasn’t always out of joy. Lynch could be frustrating, reclusive and vulgar, and the chuckles often were the only way you could think to respond to the audacity of his antics. There was the “Ghost Ride The Duck” moment in which he commandeered a “Ride The Ducks” vehicle during the Seahawks’ championship parade as it cruised the city. There was the time, on the way to a playoff game, he parked his Lamborghini in front of a Top Pot Donuts and hustled inside for a snack. He ran for 140 yards and two touchdowns that day. And, of course, there were his silent media protests, complete with his Super Bowl interview catchphrases of “I’m just ’bout that action, boss” and “I’m just here so I don’t get fined.”

But through it all, through the funny and the infuriating and the flummoxing, Lynch won over Seattle with his relentlessness. He always brought the fight. For as uncomfortable as he made some with his behavior, Lynch epitomized character on the football field.

Seattle has witnessed a few stars in other sports with bigger national reputations: Ken Griffey Jr., Gary Payton and Shawn Kemp, Ichiro when he first came to the big leagues. When he’s done playing, Russell Wilson probably will hold the title of greatest Seahawk ever. And as a unit, the “Legion of Boom” will be remembered as the leaders of the powerful defense that led the Seahawks during their Super Bowl era. But if you’re talking about the most influential player, it was Lynch.

He was the ego and the grit of a Seahawks team that won Super Bowl XLVIII following the 2013 season, a squad named its team of the decade. He was also the guy who infamously didn’t get the ball on the goal line the next year before an interception dashed Seattle’s repeat championship dreams.

Now he’s back.

“Unfinished business,” he called it recently.

It’s one of the strangest and most unlikely comebacks in recent memory. Given the timing, the stakes and how long it has been since Lynch last played, it could have an awkward, ugly ending. And no matter what happens, this figures to be a brief return because the player and team moved on from each other long ago.

But you know what else this is? Perfect. Lynch and the Seahawks are fighting together one last time, against all odds, in a high-pressure situation. For a franchise that Carroll built around the principle of competition, this is it in its highest form. And of all the competitors that Carroll and General Manager John Schneider have brought to Seattle, few compare to Lynch.

As old and new collide Sunday, Lynch is certain to be the one initiating contact.

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