The Brazilian duo are expected to be the next high-profile departures from Ukrainian football, due to the unstable political situation in the country.
Playmaker Costa has been linked with clubs across Europe, including Manchester United, Arsenal and AC Milan.
Holding midfielder Fernando has also been generating plenty of speculation, with Serie A side Fiorentina reported to be closing on his signature.
Shakhtar, who have offloaded the likes of Fernandinho and Willian in the recent past, are reluctant to part with either of their star turns during the current window.
Lucescu is, however, aware that every player has a price and that his hand may be forced if enticing offers are tabled.
He told Tuttomercatoweb.com: "Everyone talks, everyone writes, but the truth is that so far there is nothing.
"However, I am sure that things will come out in the next few days, that the final transfers will be made.
"I speak in general and I repeat that, for me, all players are transferable. In the past I have allowed players like Fernandinho and Willian to go.
"Douglas Costa and Fernando are important players for me. If we keep them it will be a good thing, but I know that sooner or later they will leave."