A Bola says United and Sporting Lisbon have made huge progress in negotiations.
Fernandes was set to feature in Friday's clash with rivals Benfica, but the report claims he could now miss the match with the deal close to being completed.
Sporting, however, reportedly remain confident he will still be able to play in the match.
The fixture could prove to be Fernandes' last game for Sporting and an opportunity to say goodbye to supporters at the Jose Alvalade Stadium.
With United officials in Lisbon, talks have accelerated after they reportedly upped their offer, which will either be structured as a £50m fee plus £8m in bonuses or £55m plus £4m in bonuses.