Former Liverpool midfielder Naby Keita has been suspended by Bundesliga club Werder Bremen until the end of the season and handed a "substantial fine" after he refused to travel with the team for their match against Bayer Leverkusen on Sunday.

The 29-year-old Guinea international "chose not to travel to the ground with the team and decided to go home instead" upon learning he was omitted from the starting lineup, according to a club statement. Bremen went on to suffer a 5-0 defeat as Leverkusen clinched their first German league title.

"As a club, we won't tolerate Naby's behavior," said Werder Bremen sporting director Clemens Fritz. "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."

The suspension and fine mark the culmination of a frustrating first season for Keita at the Weserstadion following his free transfer arrival from Liverpool last summer. Injuries have restricted the once-promising midfielder to just five appearances across all competitions.

Keita, who joined Liverpool in 2018 for a then-club record £52.75 million ($65.3 million) fee from RB Leipzig, took to Instagram to refute Fritz's initial accusation that he refused to travel. He claimed the sporting director was attempting to "tarnish his image."

However, Werder Bremen doubled down with their disciplinary action against a player whose "own interests" superseded the team's according to Fritz. "The club have also handed the midfielder a substantial fine. The 29-year-old will no longer train with the team or be part of the first-team dressing room," their statement read.

The incident further clouds Keita's future after an injury-plagued stint at Liverpool where he scored 11 goals in 129 appearances over five years, failing to recapture the form that prompted the hefty transfer fee.

Head coach Ole Werner had foreshadowed consequences for Keita's actions, stating after the Leverkusen match: "He will have to face them." The decision to suspend the midfielder underscores Werder Bremen's stance of not tolerating indiscipline that jeopardizes team cohesion.

"We won't tolerate Naby's behavior. He let his team down in a time of difficulty...and put his own interests above those of the team," Fritz reiterated, citing the club's determination to maintain standards even as injuries mounted during their underwhelming campaign.