Cleveland Browns defensive end Myles Garrett has failed in his appeal against a season-ending indefinite suspension from the NFL.
Garrett was punished after attacking the Pittsburgh Steelers quarterback Mason Rudolph with his own helmet after ripping it his head in a melee late in last Thursday's match.
Pittsburgh's Maurkice Pouncey had his suspension reduced from three games to two. The centre punched and kicked Garrett in retaliation for the attack on Rudolph.
Garrett's team-mate Larry Ogunjobi will serve a one-game ban for pushing Rudolph to the ground in the aftermath of the incident. The suspended trio were all ejected from the game.
An NFL statement read: "Appeals officers Derrick Brooks and James Thrash, jointly appointed by the NFL and the NFLPA (NFL Players' Association), have reached their decisions on the discipline appeals for Myles Garrett and Maurkice Pouncey following last week's Pittsburgh-Cleveland game.
"Thrash has upheld all discipline issued to Myles Garrett.
"Brooks has reduced the suspension of Maurkice Pouncey from three games to two games and upheld the 35,096 US dollars (£27,198) fine."
The original decision specifies that Garrett is "suspended without pay indefinitely – at a minimum for the remainder of the regular season and post-season – and must meet with the commissioner's office prior to a decision on his reinstatement".
After the game, Garrett stated to NFL.com that he "made a mistake, I lost my cool and I regret it", adding: "It was embarrassing. It was out of character but it was a situation like that, it is an emotional game, and I allowed myself to follow through those emotions."
He issued a formal apology via the Browns' Twitter feed the next day in a statement which read: "I made a terrible mistake. I lost my cool and what I did was selfish and unacceptable.
"I know that we are all responsible for our actions and I can only prove my true character through my actions moving forward.
"I want to apologise to Mason Rudolph, my team-mates, our entire organisation, our fans and to the NFL."
Garrett, 23, was the first overall pick of the 2017 draft and has 30.5 sacks in 37 career games, including 10 this season.
The Browns won last week's game 21-7. The AFC North rivals meet again at Pittsburgh's Heinz Field on December 1.