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 during Sunday's game.

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

Greenlaw will miss San Francisco's game next Monday night against Washington unless he wins an appeal.

The incident happened in the second quarter of the 49ers' 32-29 win over the Seahawks.

Sam Darnold scrambled and went out of bounds, and Greenlaw hit him late.

That drew a personal foul.

Several Seahawks defenders then confronted Greenlaw, and he responded by head-butting Jones.

Jones was bleeding after the hit, and Greenlaw was ejected.

Coach Kyle Shanahan said after the game that players get "baited big time" on an opponent's bench.

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

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

He added that they cannot do that.

Greenlaw has a history of infractions.

He was ejected twice before.

In 2023, he had a sideline altercation with Philadelphia's head of security.

In 2022, he made a helmet-to-helmet hit on Justin Herbert.

He was also suspended one game last season while with Denver for berating an official.

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

Greenlaw returned to San Francisco this season and has 37 tackles in five games.