The NFL has suspended Detroit Lions safety Brian Branch for one game without pay on Monday, citing unsportsmanlike conduct following the team’s loss to the Kansas City Chiefs.

Branch threw a punch at Chiefs wide receiver JuJu Smith-Schuster on Sunday night, triggering a brief postgame brawl.

“Your aggressive, non-football action was completely unjustified, created a serious risk of injury, and violated the standards of conduct and sportsmanship expected of all NFL players,” Jon Runyan, the league’s vice president of football operations, wrote in a letter to Branch. “Your behavior reflected poorly on the NFL and has no place in the game.”

The Lions (4-2) will face NFC South-leading Tampa Bay (5-1) without Branch, another setback for a secondary already dealing with multiple injuries.

Branch will be allowed to rejoin the active roster on Tuesday, Oct. 21, during the team’s bye week ahead of their home matchup against NFC North rival Minnesota on Nov. 2.

Following Kansas City’s 30-17 victory, quarterback Patrick Mahomes extended his hand toward Branch, who ignored him and walked past. Smith-Schuster then approached Branch, and after exchanging words, Branch swung a right hook that sent the receiver to the ground.

Smith-Schuster immediately jumped back up and went after Branch. Chiefs running back Isiah Pacheco tried to separate them, but Branch ripped off Smith-Schuster’s helmet as several players rushed into the altercation.

Smith-Schuster ended up with a bloody nose.

“I did a childish thing, but I’m tired of players doing things after the whistle and refs missing it,” Branch said after the game. “They try to bully me out there and I don’t—I shouldn’t have done it. It was childish.”

Branch was previously fined $23,186 for facemask and unsportsmanlike conduct penalties in a game against Green Bay last month.

“I love Brian Branch, but what he did is unacceptable and won’t be tolerated here,” Lions head coach Dan Campbell said Sunday night. “That’s not who we are. I apologized to coach Andy Reid, the Chiefs, and Smith-Schuster. It’s not OK. It’s not what we stand for. He knows it, and so does our team.”

Detroit drafted Branch from Alabama in the second round of the 2023 draft, and he’s become one of the franchise’s cornerstone players during its recent resurgence. He made the Pro Bowl last season after finishing fifth in AP Defensive Rookie of the Year voting.