On Sunday afternoon, the former Liverpool midfielder was not present in the squad for the fixture against champions-elect Bayer Leverkusen.
In the grand scheme of things, Keita's absence from the starting lineup was not a surprise with his only start all season coming all the way back in October.
However, it was soon claimed by the German outfit that Keita had opted against travelling with the rest of the squad to the BayArena once it emerged that he would not be in the first XI.
How did Keita respond?
The 29-year-old has since refuted the accusations of Bremen, saying in a statement on social media: "I wish to clarify my situation at my club Werder Bremen.
"Ever since I arrived at this magnificent club, I have always shown my professionalism. I have always tried to help the club and the great supporters, especially during this time of poor results.
"Since the start of my career I have never had problems with my discipline and have always shown an exemplary attitude. I will not accept any person trying to tarnish my image.
"To the supporters, I have always worked hard in training to get the right result at the weekend. In training I can only give my best. And to my teammates, good luck for the match."
Bremen would subsequently go on to lose 5-0 to Xabi Alonso's conquering side, suffering a fifth defeat in six games that has left them five points clear of the relegation zone.
Bremen release official statement
Despite Keita's comments, Bremen has taken the decision to remove Keita from the first-team picture for the rest of 2023-24, reiterating that he "let his team down".
In a statement, head of professional football Clemens Fritz said: "As a club, we won't tolerate Naby's behaviour. He let his team down in a time of difficulty surrounding our recent run of form and squad availability and put his own interests above those of the team.
"We can't allow that. At this stage of the season, we need full focus on the remaining games and a team who stick together. That's why we've been left with no alternative."
Bremen added that Keita would not be allowed to train with the first team and has also received "a substantial fine".
Since leaving Liverpool to sign for Bremen on a free transfer last summer, the Guinea international has made just one start and four substitute outings, accumulating only 106 minutes of football.