The row between Sporting Lisbon and Wolverhampton Wanderers has taken a nasty turn.

The Portuguese club have demanded that Wolves pay them £48 million. If they do not get that payment, they want FIFA to ban the club from the transfer market.

At stake is the transfer of Sporting goalkeeper Rui Patricio, who is among many players who requested a free transfer from the club after an incident where fans attacked players at the training ground.

Patricio terminated his contract at the start of June. He eventually joined Wolves.

Patricio stated at the time: "I was the victim of physical and psychological violence, so in order to preserve my personal and professional dignity, I wish to end the contract that ties me to Sporting."

Sporting claim that contract termination is not valid, which is why they want a fee from Wolves for Patricio.

It is unclear how FIFA would view matter, given the turmoil at Sporting.