The Toffees have been linked with a summer move for the 22-year-old Brazilian in recent weeks.
New Sporting coach Rúben Amorim wants to keep Wendel, meaning only a great offer will lead to a sale.
The price mentioned in the British press has been €20m, but A BOLA reports that Sporting would only negotiate at €30m.
Wendel has a €60m release clause in his contract, putting the Portuguese club in a strong position.
Signed from Fluminense in January 2018 for €7.5m, the Brazil under-23 international is under contract with the Leões until 2023.
This season, Wendel has scored two goals in 30 appearances for Sporting.