"For six million euros in this market, hombre, you don't get many players like Sandro," Gris told Sky Sports.
"Malaga gave him confidence and trust and it paid off.
"Everyone was surprised by how he could strike a ball but this is a guy who trains hard, who wants to improve and who is football-mad.
"You can see that he was made to be a professional. If you make him an important player from the start, he will repay you.
"The speed and the end-to-end nature of the Premier League will suit him."