Manchester United manager Erik ten Hag fears Antony has suffered a "serious" injury against being stretchered off against Chelsea.
The forward appeared to be left in agony after an innocuous-looking challenge by Trevoh Chalobah. He did try to carry on after medical attention, but was soon back on the turf and then carried off in tears.
Luke Shaw was also withdrawn earlier than expected, not appearing again after half-time with Tyrell Malacia coming onto replace him.
Ten Hag addressed the pair to Sky Sports, but was vague in his answers. He said: "It’s difficult to say. Let’s wait 24 hours and then we will know more."
It was a more concerning update shortly afterwards in his press conference, adding: "I can tell you it is serious but we have to wait a minimum 24 hours and then we will probably know more about the status of his injury."
United host Fulham in their final game of the Premier League season on Sunday before taking on Manchester City in the FA Cup final the following Saturday.
Gary Neville expects Antony is now a major doubt for the Wembley derby.
"It’s the reaction of a player that’s going to spend some time out of the game," Neville said on Sky Sports. "His hand was slamming the ground. I’d be amazed if he does carry on, but he has just stood up.
"[en Hag] will now be thinking he’ll have to rethink this game but he’s also got Sunday against Fulham at home to fill in that right-hand side, because Antony would be a shoe-in for that cup final side."
