Manchester United manager Erik ten Hag could not provide any positive updates on the injury suffered by Raphael Varane in Saturday's 1-1 draw with Chelsea.
Varane had impressed at Stamford Bridge but was forced off in the second half after overextending himself while trying to cut out a pass to Pierre-Emerick Aubameyang.
The France international clearly looked distressed as he left the pitch, pulling his jersey up above his eyes as if trying to hide tears.
Any serious injury suffered by Varane at this point would put the defender's World Cup participation in doubt at the very least, and probably rule him out entirely.
Ten Hag acknowledged Varane's initial reaction may have provided an indication of the severity, but it was too early to be sure.
Asked if there was an update on Varane's condition, Ten Hag told Sky Sports: "Nothing, actually.
"I know he's injured otherwise he'd not be coming off, but we have to wait 24 hours for the diagnosis and then we'll know more."
When pressed for more information regarding Varane's emotional reaction, Ten Hag added: "It's not possible [to know the extent of the injury].
"He feels [emotional], and that gives a certain perspective, but we don't know. You have to wait a minimum of 24 hours, maybe even more when it's that injury."
Cristiano Ronaldo missed the game after he was dropped as a consequence of refusing to come on as a substitute against Tottenham on Wednesday.
United were somewhat wasteful in the first half, with Marcus Rashford and Antony missing a presentable chance each, and Ten Hag acknowledged the Red Devils missed having Ronaldo as an option, with their late equaliser coming via a Casemiro header.
"As always, he can score a goal," Ten Hag said. "He's valuable for us and we need him, it's clear, and I think you see it also in this game. He can finish off, it's obvious."
But Ten Hag would not say any more on the subject of Ronaldo when asked if he was confident of resolving the matter to everyone's satisfaction, instead preferring to concentrate on Saturday's performance.
"I think I've said enough about the situation," the Dutchman said. "Let's focus on the game. It was a good game from my team and I have to really compliment my team for this.
"If you can deliver this after four games in 10 days, if you then dictate this first half and in the second half you are well organised and then fight back, I think that has to be the focus."