Chelsea have already been warned by FIFA that they will be forced to field their strongest team in next summer's Club World Cup.
The Blues and Manchester City will be representing England in that tournament held in the United States after the regular season finishes. Chelsea and City have qualified for the Club World Cup by virtue of winning the Champions League over the course of the last four years.
The two sides have also played in the Club World Cup previously. However, then the tournament consisted of just eight teams and was hosted in December. Now, the competition has been moved to the end of the campaign, and will last a month, involving 32 clubs from across the globe.
Professional clubs in Europe have protested against this decision citing player welfare as one issue owing to there being effectively no break. Should Chelsea reach the final, they will be playing until July 13 with the Premier League season then set to start on August 16.
As such, Chelsea and City had hoped to play weakened squads in the tournament. Cole Palmer was left out of the Blues' Conference League squad to rest him after a busy summer - but FIFA has confirmed they will block attempts from clubs to leave players at home for the tournament.
Instead, FIFA has allowed participating clubs to open their transfer window from June 1 and shall close it five days before the tournament begins on June 10. This decision was made to allow clubs to sign new players to play in the tournament.
It is unclear, at this stage, how FIFA will manage to police teams from fielding weaker squads at the tournament. Pep Guardiola has also claimed that the Premier League will not allow either City or Chelsea to start their Premier League campaigns later to allow their players an extended break.
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