Fabian, 23, has been linked with numerous European giants, namely Real Madrid and Barcelona.
The Spain international is contracted until 2023 with the Serie A side, but reports have suggested he could sign a new deal.
However, his agent, Alvaro Torres, said any talks over a new contract would have to wait.
"At the moment he's focused on Napoli," he told Marca.
"They've faced a lot of changes, including Carlo Ancelotti's sacking and they've had a difficult year.
"We've parked the renewal for now until the end of the season."
Fabian has made 32 appearances for Napoli this campaign, impressing to attract interest from elsewhere.
Torres said several big clubs had asked about Fabian, who he expects to become one of the world's best.
"Obviously a lot of important clubs have asked about him and his situation, and we've told Napoli," he said.
"But now Fabian has to think about Napoli and it's natural that these things happen after he was the best player at the European Under-21 Championship and he's had three good seasons.
"We all agree that he's going to be one of the big players this decade."