The teenage striker is widely regarded as a star of the future, and has also attracted attention from Atletico Madrid, despite having made just five first-team appearances for the Dutch giants.
Red Devils boss Sir Alex Ferguson is believed to be monitoring the 18-year-old's situation with keen intent, as he considers a bid to hijack the player and bring him to Old Trafford.
Ajax offered the Danish star improved terms in the past two weeks, but Fischer's agent, Soren Lerby has revealed that there will be no official discussions until the New Year.
"We will continue to negotiate after the Christmas holidays," Lerby told Tipsbladet. "Viktor is playing and that is good for him. That is the only focus right now."
Manchester United already have plentiful options in attack following the £24million summer signing of Robin van Persie, adding to an already fearsome front-line that includes Wayne Rooney, Danny Welbeck and Javier Hernandez.
A move for Fischer would be very much regarded as one for the future, with the possibility of the Eredivisie starlet being loaned back to his native Holland to continue his development with regular first-team football.