Keita, 29, “decided to go home instead” after learning he wouldn’t start the game, according to the club.
Leverkusen won the Bundesliga championship, and Werder Bremen suffered a 5-0 defeat.
“Naby’s actions will not be accepted,” Clemens Fritz, the director of football, stated.
“He put his personal interests ahead of the team’s during a difficult period involving our recent run of form and squad availability, letting his team down.”
That is not acceptable. We need to keep focused on the remaining games of the season and have a cohesive team at this point in the campaign. Because of this, we are without a choice.”
As part of his punishment, the Guinea international will not be allowed to train with the team or use the first team changing room.
After five seasons at Liverpool, he signed a contract with 12th-place Werder in June 2023. Despite this, he has only made five league appearances and one start for the German team.