Fletcher has been strongly linked with a move to Premier League side Sunderland in recent days.
Moxey told the Express and Star: “We are not getting drawn on offers for players in or out.
“Our best players are not for sale, we want to keep them and build the strongest possible team for the season ahead.
“We will do everything we can to retain the players we want to keep and continue to look to strengthen with new signings.”
