Manchester United fear winger Antony has suffered a recurrence of the ankle injury that kept him out of the final two months of last season with Ajax.
The Brazil forward was taken off on a stretcher in tears after an innocuous challenge in the win against Chelsea.
The 23-year-old missed the last eight games of Ajax's 2021-22 campaign after suffering the initial injury in a World Cup qualifier for Brazil in March 2022.
He has scored eight goals since joining United in September for £81m.
Victory against Chelsea secured Erik ten Hag's side a place in next season's Champions League and they face Manchester City in the FA Cup final on 3 June.
