The Major League Baseball Players Association filed a grievance against the league, claiming MLB did not act in good faith to play as many games as possible during the 2020 season, sources told the New York Post's Joel Sherman.
The players association seeks an estimated $500 million in damages.
The union has not indicated how many more contests it believes clubs should have played, but $500 million in damages would translate to about 20-25 games of pay for players, according to Sherman's sources.
The league has also requested the union fast-track the grievance since the collective bargaining agreement expires on Dec. 1.
MLB played 60 regular-season games during the 2020 campaign, with players receiving their full pro-rated pay - equal to about 37% of their full salaries.