The 24-year-old, who has been in stunning form over the past 12 months, told Portuguese TV channel SIC he does not know where he will play next term, but he assured fans he will not depart Lisbon purely for financial gain (h/t Jake Polden of the Mirror).
Fernandes said he has "dreams to be fulfilled" in his career but stated his family are settled in Portugal.
"I honestly don't know [what will happen in the future]. I like to focus on things once the season is over, when I can think with calmness.
"The financial aspect always weights a lot, we have a short career. But staying here, I will always be able to raise money, it's not a financial issue.
"It's a matter of having dreams left to realise. It's a difficult choice, we never know what's going to happen. My connection to Sporting is very strong and it was even stronger after the events [in Alcochete] and having come back [to Sporting].
"It meant a lot to me how I was received, I'm close to home, I have my family, my daughter can grow up more easily at school, but there are dreams to be fulfilled in my head and which I would like to achieve."
Fernandes' reputation exploded during the last campaign, but his club ended the season 13 points behind Primeira Liga winners Benfica.
The Premier League champions have multiple world-class options in the centre of the field, but United are desperate to purchase burgeoning talent for their stale squad.
Per SIC, Fernandes added the forthcoming decision about his career has made him feel emotionally conflicted. Sporting ended the season with victory in the Portuguese Cup, beating Porto 5-4 on penalties after losing last year's final 2-1 to Desportivo Aves.
"It hurts a lot to hear people say 'stay,' and I do not know the future," Fernandes said. "Especially after the [Portuguese] Cup final, when I went up the stairs [to collect the Cup], a lot of people asked me to stay. Those same people last year were crying out of sorrow, and it was different to now see them crying with joy."
Fernandes has the ability to be parachuted into one of England's top sides, and Sporting will struggle to hold onto a talent at the top of his value in a spiralling market.
United manager Ole Gunnar Solskjaer needs to find a player who can both score from midfield and provide his attackers the creativity they crave from deep.
Fernandes is also a set-piece expert, and he could become the heartbeat of the Red Devils side if he opts to move to Old Trafford.