It is unclear whether or not any of that money would be owed to Sunderland.
Sporting are looking to sell Sebastian Coates for around four times the price they paid Sunderland two years ago, according to O Jogo.
Coates joined the Lisbon side in a reported €5 million (£4.3 million) deal following a successful loan spell and has since become one of the team’s most senior figures.
But the Portuguese website claims that despite the 28-year-old having proved a successful recruit, Sporting’s well-documented financial limitations have left them open to losing the former Sunderland centre-back.
It adds that a fee of £20 million (£17 million) – less than half of Coates’s buyout fee – would be acceptable to the Lions.
And it is unclear whether or not any of that money would be owed to Sunderland as part of an agreed a sell-on clause.
Coates is already said to have been the subject of approaches from clubs in China and Spain, including Valencia.
Did Sunderland make a mistake selling Coates?
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