The Brazilian's representative says the Giallorossi have not allowed him to talk to any other clubs amid reported interest from Barcelona
The 19-year-old enjoyed a stellar first season in the Italian capital and has since been heavily linked with a move to Camp Nou.
However, the former Corinthians youngster's representative, Roberto Calenda, has insisted that there have been no talks with any club, with the Giallorossi eager to keep the Brazilian.
"The player has a contract for four season with Roma and he will surely stay," he told Sky Sport Italia.
"There are no negotiations ongoing. It's normal that there are lots of teams interested in him because we're talking about a very talented guy.
"But Roma have not allowed us to talk to anyone."
Calenda also slammed the level of press intrusion into his player's private life after he was pictured in a Rome restaurant.
"Marquinhos was sent home this morning because he had a fever. I went to visit him and we went to the restaurant in front of his house because he had nothing to eat at home.
"Roma know everything, but unfortunately there are people who take pictures without knowing things and you cannot have a private life."