Chelsea are watching Lucas Ocampos' situation at Sevilla.
The Argentina attacker only left Olympique Marseille for Sevilla last summer for €15m.
However, Italian transfer expert Gianluca di Marzio says Ocampos' form is already attracting enquiries from across Europe.
Chelsea and Bayern Munich have both been in contact about Ocampos' plans.
The goalscoring midfielder, 25, has a contract with Sevilla to 2024.