According to Record, the principality club approached Sporting with an offer of €15m for Wendel.
In response, Sporting pointed to a €25m as a minimum starting point for negotiations.
23-year-old Wendel is under contract with the Lisbon club until June 2023 and has a €60m release clause.
He is viewed as an ideal heir to Allan in Naples, but the Italian club face competition from Monaco.
Monaco have also been associated with Florentino Luis who plays for Sporting’s local rivals Benfica.
Wendel made 39 appearances for Sporting last season, scoring three and assisting two goals.