Flamengo have been credited with an interest in Castan, but the player has said that he intends to see out the final three years of his contract.
"I have three more years of contract with Roma. I don't even worry much about the enquiries," he told Globo Esporte.
"My father handles my career, so I leave everything in his hands. Now I just want to rest without paying much attention to speculation."
Castan joined Roma last summer from Corinthians and has made 13 Serie A appearances for the club.