The ruling by jointly appointed appeals officer James Thrash confirms that Garrett will sit out the rest of the season, including any playoff games, for swinging Mason Rudolph's helmet at the quarterback in the final seconds of last Thursday's game.
Browns general manager John Dorsey released a statement shortly after the ruling was made public:
Meanwhile, Pittsburgh Steelers center Maurkice Pouncey's three-game ban was reduced to two games. Pouncey - who was disciplined for kicking a downed Garrett - will miss the rematch between the Steelers and Browns in Week 13.
Garrett was also fined $45,623, a source told Ian Rapoport of NFL Network.
Pouncey's fine of $35,096 was upheld by the other appeals officer, Derrick Brooks.
During his appeal, Garrett reportedly accused Rudolph of using a racial slur prior to the brawl, an allegation that the quarterback "vehemently denies."
When Garrett's suspension was first announced, the league said he would be required to meet with commissioner Roger Goodell "prior to a decision on his reinstatement."