SEATTLE — There’s a reason why he’s your favorite 49er’s favorite Niner.

He’s the spiritual partner to fellow linebacker Fred Warner. Nick Bosa called him “my favorite teammate I’ve ever played with on the field.” In public, coach Kyle Shanahan refers to him as a “family member.” Behind the scenes, general manager John Lynch revealed this week on KNBR, Shanahan has another nickname for Dre Greenlaw: Mike Tyson.

“For a reason,” Lynch said. “He’s a ferocious competitor. And it’s great to have him on our side.”

Lynch’s comments came after Dre Greenlaw channeled his emotions into a team-high 12 tackles against his former team, the Broncos (and some choice words for Sean Payton). Just one week later, the 49ers learned (as they have in the past) that it cuts both ways.

After all, just ask Evander Holyfield. 

Or, in this case, Ernest Jones IV.

Thankfully, Jones’ ears remain intact. But the bare head of the Seahawks linebacker took a bruising when Greenlaw head-butted his helmeted noggin into Jones’ unprotected face after finding himself in a sea of blue on the Seattle sideline. The late hit on quarterback Sam Darnold that put Greenlaw deep into enemy territory all by himself in the second quarter of the 32-29 win was harmful enough, drawing a 15-yard personal foul, but his actions after the whistle blew proved to be even more costly.

The NFL on Monday handed down a one-game suspension to Greenlaw. He will get the chance to make his case in an appeal hearing Tuesday, but for now, the 49ers have to prepare as if they’ll be without their No. 2 linebacker when they host the Commanders on Monday night.

Shanahan said on a conference call with reporters a few hours after the NFL announced its punishment that he “was disappointed they decided to do that … but you’ve got to deal with it.”

What was the league supposed to do?

If the league is serious about head trauma, it can’t have unhelmeted players taking blows (even if they happen to grab another player’s face mask in a moment where emotions run high). On top of that, Greenlaw has a history that you can bet the league office is taking into account.

He’s taken it too far in the past, whether it was berating an official that earned him a one-game suspension last season, the sideline altercation he got into with Eagles head of security Dominic “Big Dom” DiSandro in 2023 or his helmet-to-helmet hit on Justin Herbert the season before.

Before the game had even gone final, Greenlaw had a message up on his personal Instagram: “Yall [sic] just a money stealing organization,” he wrote, tagging the NFL. (Greenlaw was fined almost $12,000 for taunting the Broncos sideline last week.)

After the game, Shanahan said Greenlaw had been “baited” by their archrivals. Well, he was basically baiting the NFL for a harsher response with his reaction to his ejection.

It was another unfortunate case of Greenlaw acting first and thinking later. He deleted the post quickly after it went up. But there’s no delete button for head-butting an opponent.

That’s an act you can’t take back.

“We’ve got to be a lot smarter than that,” Shanahan said. “He knows he’s got to be smart.”

For all of the good that comes out of Greenlaw’s Mike Tyson side, he has to do a better job of controlling his emotions. His passion, energy and competitive spirit fuels the 49ers. It has played no small part in getting them to two Super Bowls and off to a 5-0 start this year.

But he is a double-edged lightning rod, and the 49ers caught the wrong end this week.

Everybody else on the field could feel the same intensity of a heated rivalry game. Greenlaw was the only one who gave himself permission to take it over the top.

Jones was asked after the game how much restraint he had to display in the moment. While he initially went for Greenlaw’s face mask, he quickly pulled back and put his hands in the air.

“A lot,” he said.

At least one player set the right example in the scrum that erupted on the Seattle sideline. 

Greenlaw chose fight over flight, but the initial emotions that preceded his poor judgment were totally reasonable. He was surrounded by Seahawks already predisposed to dislike him and put on tilt with his hit on their quarterback, who already had two feet out of bounds.

There wasn’t a teammate in sight. Warner, eventually, forced his way through the sea of blue jerseys and pulled Greenlaw to safety. But it was too late. The deed had been done.

“I tried to get there as fast as I could,” Warner said. “I was too far away. 

“He’s helpless in that situation, he’s all by himself on their sideline, and of course they are trying to gang up on him. … But we know we have to be smart in all those situations, and I thought Dre tried for the most part. But it’s just an unfortunate situation.”

Seahawks coach Mike Macdonald confirmed that Jones came away no worse for the wear.

The real victims? The same teammates who have sung Greenlaw’s praises all season.

They were the ones who were forced to pick up the slack as Greenlaw was forced to watch the final two-plus quarters from the locker room. Now, they have another four quarters ahead of them that they’ll have to cover for him — and will be down another linebacker, with second-stringer Garrett Wallow suffering a hamstring injury that will keep him out a few weeks.

The fire Greenlaw plays with has been an overwhelming positive for both himself and the 49ers. It’s how he’s forged an eight-year career with a reputation as one of the NFL’s hardest-hitting linebackers, and it’s why he’s so beloved inside the walls of the 49ers’ building.

But it’s time to set a few ground rules.

No head-butts. No ear-bites. 

Capisce?