The 22-year-old joined the Tuscan outfit from Colombian club Atletico Nacional this summer, despite alleged interest from the likes of Roma and Palermo.
The Stadio Franchi team paid €2.4m to secure his services, but the youngster has showed great maturity in the first months of this campaign and it is alleged that his transfer fee has now raised to over €3m.
Old Lady sporting director Alessio Secco is reportedly keen on the full-back, as confirmed by one of Siena executives.
“We have indeed talked about him on the phone,” Gerolin is quoted as saying in Tuttosport.
“Even though we cannot really say we have started negotiating, we have a great rapport with Juve that was strengthened with the deals regarding Cristian Molinaro and Paolo De Ceglie.
“I would almost say we are allied and are prepared to listen to their offers, if they really confirm their interest.”
Gerolin was the one who unearthed Cristian Zapata for Udinese and also tracked Zuniga in Colombia for several months.
“He is 22, but I have been following him ever since he played at Under-17 level, and we managed to sign him last July,” he concluded.