Marshawn Lynch surprises Mike Macdonald during Seahawks coach’s debut. As only Lynch could

As meticulous as Mike Macdonald is — “nerdy,” he himself admits —the new coach prepared for everything he could conceive before his first game in charge.

Except this.

He could not fathom Marshawn Lynch giving him a shoulder rub on the sideline in the middle of his first Seahawks game.

With 2 1/2 minutes remaining in the first quarter of Seattle’s opener against Denver at Lumen Field Sunday, Macdonald was preparing to call a defensive play. It was the start of the Broncos’ fourth possession. The game was tied at 3.

Lynch was visiting Sunday, along with former Super Bowl-champion teammates Doug Baldwin and Kam Chancellor plus Hall-of-Famer Steve Largent for the team’s throwback game.

Lynch, the franchise’s retired, iconic, one-of-one running back, walked up to Macdonald along the edge of the field.

Lynch began rubbing the bottom of the intense coach’s neck and top of his shoulders. Then he joked with Macdonald.

The stunned Macdonald gave what appeared to be a nervous, if not forced, smile. Then he laughed.

He kept looking down at his call sheet of defensive plays.

“Is that what he did?” Macdonald said later.

“I guess I blacked out.”

It was so Lynch.

It was so not Macdonald.

It was the most unexpected thing the NFL’s youngest head coach experienced in his first game in charge, the Seahawks’ 26-20 victory to begin their Mike Macdonald Era.

“Yeah, never had a former player talk to me mid-game,” the 37-year-old former Baltimore Ravens defensive coordinator said.

“It’s pretty cool. I was like, we have another three quarters to play.”

Macdonald laughed.

“It’s awesome. He’s one of my favorite players of all time. He’s incredible. Yeah, funny. Came up right behind me. I found myself talking to him as they were taking the field.

“I was like, ‘Oh, shoot! I need the call on first down!”

Kenneth Walker appreciates Marshawn Lynch

About 90 minutes before kickoff, Lynch walked the west sideline.

He was hugging friends — including Chancellor, his former Seahawks teammate — plus team staffers. He hugged fans he recognized from his seven seasons as Seattle’s unique, pounding running back. Those seasons included the best ones in team history, the back-to-back Super Bowl years of 2013 and ‘14 with the franchise’s only NFL championship.

As the full Seahawks roster took the field for pregame warm-ups 45 minutes before kickoff, Lynch and his former Super Bowl-champion teammate Doug Baldwin talked with Macdonald.

Lynch wore a black hoodie on his head on the 70-degree late morning under a hazy Seattle sun. Over that, he was wearing a jacket with his old jersey number 24 on the front and the Madden video-game logo over the words “Rating Performance Adjuster.”

Kenneth Walker, the latest successor to Lynch as Seattle’s lead running back, took the opportunity to talk with him.

“Yeah, definitely. Pregame, I went to talk to him,” Walker said. “He didn’t see my head, at first. Then when he saw it he started laughing — cut my hair off (recently).

“It’s always great to see the guys who played before me here. I talked to Baldwin, as well.”