FIFA's investigation of Chelsea for potential transfer rule breaches has sprawled to examine arrangements with more than 100 foreign players under the age of 18, sources have confirmed to ESPN FC.
The governing body's disciplinary committee is considering its final decision, with Chelsea expected to face a transfer ban if found guilty.
Key to Chelsea's defence against any sanction is the argument that many of the individual cases highlighted by FIFA involve short-term trialists who were not signed. There is no rule against trialing overseas players under the age of 18 and the club do not believe they should be considered in the final judgement.
FIFA transfer regulations prohibit clubs from signing under-18 players from other countries unless their parents have emigrated for reasons not connected to football or both the player and club are based within 50km of a national border.
The only other exception to this is Article 19, which allows for players between the ages of 16 and 18 to be transferred within the European Union or European Economic Area.
Chelsea's academy has been under investigation for potential transfer rule breaches since 2016, when pictures emerged of Bertrand Traore playing for the club against Arsenal in a non-competitive match as a 16-year-old.
The club said they had approval from both the Football Association and Premier League to play Traore in trial games. He left Stamford Bridge to join Lyon for £8.8 million in the summer of 2017, though it is understood that Chelsea retain the right to buy him back for an agreed price.
If a transfer ban is imposed, Chelsea will have the right to appeal to FIFA and then to the Court of Arbitration for Sport (CAS) if necessary.
FIFA have previously investigated Real Madrid, Barcelona and Atletico Madrid for breaching rules relating to the signing of players under the age of 18 and each club was subsequently given a two-window transfer ban, though Real Madrid's punishment was reduced to one window on appeal to CAS.
Chelsea declined to comment when contacted by ESPN FC, but issued a statement in November which said that they had "fully cooperated with FIFA and provided comprehensive evidence demonstrating its compliance with the applicable FIFA regulations."