M'Baye Niang has opted against joining Watford permanently following the end of his loan spell.
The French striker, 22, joined the Hornets on loan from AC Milan in January and scored two goals across his 11 Premier League appearances.
Watford have undergone a change of head coach since the English season ended, with Marco Silva replacing Walter Mazzarri, and even though he expects to receive overtures about a permanent move to Hertfordshire, Niang believes his own future lies back in Milan.
He told L'Equipe: "I owe a lot to the club that gave me a chance to play in a different championship, to experience a new mentality, and that allowed me to play as regularly as I would have liked to.
"But even if Watford have an option to purchase that the management wants to activate, I do not see myself staying there. And that is only for personal reasons.
"I have given myself time to reflect, I weighed up the pros and cons and despite the great opportunity offered by Watford, I do not think my future lies there.
"I ask them to be understanding and accept my decision, which is irrevocable because I will not change my mind."