SEATTLE, WA (AP) – The Seattle Sounders players wore T-shirts before a match Sunday that read “Club World Cup Ca$h Grab” to demand a share of the prize money for participating in the upcoming international tournament.

The Sounders, one of 32 teams set to play in the Club World Cup later this month, wore the shirts before kickoff of their match against Minnesota United.

Major League Soccer’s Players Association issued a statement in solidarity with the protest.

“FIFA’s new tournament piles on to players’ ever-increasing workload without regard to their physical well-being. In order to seize this additional calendar territory, FIFA had to commit historic amounts of prize money to secure club and player participation,” the MLSPA statement said. “As a result, MLS will receive an unprecedented windfall. Despite the windfall, the league has refused to allocate a fair percentage of those funds to the players themselves.”

The Sounders are among three MLS teams taking part in the Club World Cup, along with Inter Miami and LAFC. The tournament, which features an expanded field of club teams from around the globe, starts June 14 and will be played across 11 U.S. cities.

The Sounders will earn $9.55 million as a club for participating in the tournament, with a chance to win additional prize money from wins.

The MLSPA said the players have invited the league to discuss bonus terms but that “MLS has failed to bring forward a reasonable proposal.” Currently, there is a provision of the collective bargaining agreement that caps how much prize money can go to players at $1 million.

Major League Soccer declined to comment because negotiations with MLSPA are ongoing.

The Sounders’ starters posed for the pregame photo wearing the T-shirts, which also said “Fair Share Now” on the back.

“It is the players who make the game possible. It is the players who are lifting MLS up on the global stage,” the MLSPA said in its statement. “They expect to be treated fairly and with respect.”