Football's fixture congestion row is set to intensify on Monday as leagues and unions lodge a legal complaint against FIFA with the European Commission.
The group, which includes the Premier League via its membership of the European Leagues collective, argue football's global governing body has abused a dominant position under European competition law.
They say FIFA did not properly consult over the new calendar before it was announced in March last year and that as a result the schedule has gone "beyond saturation".
The introduction of a 32-team Club World Cup every four years has been seen as the tipping point, but the bigger issue, they say, is FIFA's general conduct around this issue, alleging it has favoured its own commercial interests which has in turn "harmed the economic interests of national leagues and the welfare of players".
League sources point to Manchester City's recent request to postpone domestic matches at the start of next season in order to allow more recovery time after the Club World Cup as a prime example of how this new competition will impact on the schedule and quality of their own.
The Premier League can point to the fact that it has been a 20-team competition for almost 30 years and that fixture congestion in the club game is the result of expansion at the international level by UEFA and now FIFA.
FIFA insists the calendar announced at its 2023 Congress in Rwanda was the result of extensive consultation and that it is fully within its rights to set the parameters of its own competitions like the Club World Cup provided they fit within the agreed calendar framework.
The leagues have also been accused of "hypocrisy" by FIFA, which says these leagues "prefer a calendar filled with friendlies and summer tours" such as the Premier League's own Summer Series.
FIFPRO Europe, the continental arm of the world players' union FIFPRO, is also part of the action.
There have already been a number of instances of players speaking out about the demands of the calendar, with Manchester City midfielder Rodri saying players were "close" to striking over the issue, shortly before he suffered a season-ending injury.
UEFA president Aleksander Ceferin, who has overseen the expansion of European club competitions, said on Thursday that the calendar had "reached its limit" but added to the BBC: "Who is complaining? Those who earn the highest salaries and those teams with a squad of 25 top-level players."
"Those with lower salaries and hardly 11 players do not complain. They love to play."
The submission of the legal complaint marks the third consecutive week where a competition law case has made the football headlines.
On October 4 the European Court of Justice found some of FIFA's transfer rules breached competition and freedom of movement law in the case of former Arsenal, Chelsea and Portsmouth midfielder Lassana Diarra.
Last Monday the Premier League's associated party transaction (APT) rules were found to be unlawful in certain aspects by an arbitration panel after a challenge was brought by Manchester City.
