The NFL suspended San Francisco 49ers linebacker Dre Greenlaw for one game on Monday.

The league said he head-butted Seattle's Ernest Jones IV without a helmet.

This happened during Sunday's game.

The NFL said the act was "contrary to the generally understood principles of sportsmanship."

Greenlaw will miss San Francisco's game next Monday night against Washington.

He will miss it unless he wins an appeal.

The incident happened in the second quarter.

The 49ers beat the Seahawks 32-29.

Sam Darnold ran and went out of bounds.

Greenlaw hit him late.

That was a personal foul.

Several Seahawks players then confronted Greenlaw.

He responded by head-butting Jones.

Jones was bleeding after the hit.

Greenlaw was ejected.

Coach Kyle Shanahan spoke after the game.

He said players get "baited big time" on an opponent's bench.

He said he was told Greenlaw butted a player without a helmet.

Shanahan said if that is what happened, the team has to be smarter.

He said they cannot do that.

Greenlaw has a history of breaking rules.

He was ejected twice before.

In 2023, he had a fight on the sideline with Philadelphia's head of security.

In 2022, he hit Justin Herbert helmet-to-helmet.

Last season, he was suspended one game while with Denver.

He had yelled at an official.

Last week, he was fined $11,941 for taunting the Broncos' sideline.

Greenlaw returned to San Francisco this season.

He has 37 tackles in five games.