The Argentine international could end up costing Sunderland around £8 million.
The Premier League side may have to spend £8 million on a player that they do not own, according to the Sunderland Echo.
Ricky Alvarez does not know which club possesses his registration.
Ricky Alvarez hopes to soon be finally free of his wrangle between Sunderland and Inter Milan.
Alvarez is in limbo due to disputes between Sunderland and Internazionale.
The Argentine international has been told he is free to join Porto.
The future of Sunderland winger Alvarez has still not been decided.
River Plate are hoping to sign Ricky Alvarez, as the former Sunderland loanee awaits news over his future.
Roma are looking to sign Ricky Alvarez - who Sunderland no longer want to own.
Sunderland linked Ricky Alvarez is training alone.