The Portuguese club Sporting Lisbon seek £175m compensation for three players
The Club wants compensation of up to 197m euros (£175m) for three players who terminated their contracts and have since joined other clubs.
Among the players is Rui Patricio, who joined Premier League newcomers Wolves.
Sporting want 57m euros (£50m) for the Portugal goalkeeper, 100m euros (£89m) for Atletico Madrid winger Gelson Martins, and 30-40m euros (£27m-£36m) for Olympiakos winger Daniel Podence.
Nine players quit the club after an attack at the training ground in May.
Sporting say they have reported Martins, Patricio and Podence – and their new clubs – to world governing body Fifa.
They say the Court of Arbitration for Sport (Cas) will decide whether to side with the players or Sporting.
A group of 50 fans reportedly attacked Sporting players and staff in May after the club missed out on a Champions League place on the final day of the season.