The 24-year-old has struggled during his two seasons at Old Trafford, and the Red Devils are believed to have been open to offers for him during the recent transfer market.
According to the Daily Mail, Real Betis attempted to sign Antony on loan before the window closed, but Man United rejected the offer from the La Liga outfit.
The report claims that the same team also made a loan offer for Christian Eriksen, but the Red Devils decided against allowing either player to depart in the final moments of the window.
Antony's substantial wages, which are believed to be in the region of £200,000 a week, are thought to have been one of the main reasons why Man United were unable to shift the Brazilian before the market closed.
Man United 'rejected' loan offer from Real Betis
The forward followed Erik ten Hag to Man United in 2022, penning a five-year contract at Old Trafford with the option of a further 12 months, but it has been difficult for him in Manchester.
Antony has only managed 11 goals and five assists in 83 matches for Man United, and he particularly struggled last term, scoring only three times in 38 appearances, in addition to registering just two assists.
The forward has only played one minute of Premier League football this season, featuring in the latter stages of his side's 2-1 defeat to Brighton & Hove Albion on August 24.
Antony was an unused substitute against both Fulham and Liverpool, while he also did not feature off the bench in the clash with Manchester City in the Community Shield at the start of August.
The South American will be hoping to be given the chance to impress when Man United continue their Premier League campaign away to Southampton after the international break.
Which players left Man United over the summer?
It was a busy summer transfer window at Old Trafford, with five new players arriving, including Manuel Ugarte, who joined the club from Paris Saint-Germain in the final stages of the market.
Leny Yoro, Joshua Zirkzee, Noussair Mazraoui and Matthijs de Ligt also moved to Old Trafford, while there were a host of departures, with the biggest sale proving to be Scott McTominay to Napoli.
Mason Greenwood, Aaron Wan-Bissaka, Willy Kambwala, Hannibal Mejbri, Facundo Pellistri, Alvaro Fernandez and Donny van de Beek also left for transfer fees, while Raphael Varane, Omari Forson, Anthony Martial and Brandon Williams departed on free transfers.
Jadon Sancho secured a loan move to Chelsea before the end of the market, meanwhile, and the Blues will complete a permanent deal for the Englishman next summer.