The 20-year-old came through the youth system at Sporting, and he has represented their senior side on 10 occasions, including two outings this season.
However, according to the Daily Mail, Southampton are in discussions with the Portuguese giants over a move for Fernandes, who is said to be valued by his current side in the region of £16m.
Sporting boss Ruben Amorim confirmed on Saturday that Fernandes is leaving this summer but did not mention any potential suitors for the attacker.
The youngster spent the 2023-24 campaign on loan with Portuguese outfit Estoril, scoring once in 28 appearances in the Primeira Liga.
Mourinho 'wants' Lo Celso at Fenerbahce
Meanwhile, according to Sporx, Fenerbahce are determined to complete a move for Tottenham Hotspur attacker Giovani Lo Celso before this summer's transfer window closes for business.
There is currently a host of speculation surrounding Lo Celso's future, with the Argentine expected to leave the Tottenham Hotspur Stadium over the next couple of weeks.
Fenerbahce head coach Jose Mourinho has allegedly identified the midfielder as a leading target, and a deal could go through before the window shuts.
Lo Celso is said to be 'open' to playing under ex-Tottenham head coach Mourinho again, while Spurs are keen on a sale, as his contract is due to expire next summer.
The 28-year-old has scored 10 goals and registered eight assists in 108 appearances for Spurs in all competitions, including three goals and five assists in 77 Premier League outings.
Motta reiterates Juve's Chiesa stance
Elsewhere, Juventus head coach Thiago Motta has reiterated that Federico Chiesa is free to leave the Old Lady before the end of the transfer window.
Chiesa has been linked with a move to the Premier League, with Manchester United and Arsenal believed to be keen on his services, and the Italy international is not in Juve's plans for the 2024-25 campaign.
"Our position on Federico Chiesa hasn't changed. He's not part of our plans. We've talked. It's a demonstration of the respect I have for everyone. Transparency, clarity, that's the way I communicate with my players," Motta told reporters when questioned on the transfer situation.
The 26-year-old, who is out of contract in Turin next summer, has scored 32 goals and registered 23 assists in 131 appearances for Juventus.
Chiesa made 37 appearances for the Old Lady last season, scoring 10 goals and registering three assists in the process, but he has seemingly played his final game for the club.