Jordan Henderson was taken off the pitch at Estadio Azteca on a stretcher and receiving oxygen after an incident after the game.
The Brentford midfielder was an unused substitute for England's 3-2 victory over Mexico in the World Cup round of 16, but naturally joined his teammates for the post-match celebrations.
Henderson fell over the advertising hoardings after standing in front the England fans while they belted out Wonderwall.
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Jordan Henderson 'did something to his arm' in post-match celebrations
It was a thrilling and hard-fought victory for England, who twice took a two-goal lead over Mexico only to be pegged back both times.
Jarell Quansah's straight red card just before the hour certainly didn't help matters, but Thomas Tuchel's side were able to hold on through a tense finale and set up a quarter-final tie with Norway.
England captain Harry Kane told the BBC after the game: "Jordan just fell over there, I think he's OK, just something to do with his arm."
Jude Bellingham added: "He's in a bit of bother, but our medical team have got everything under control.
"It's probably not best to give too much detail because I don't really know too much what's going on, but everyone's there to support him and even that was a beautiful thing to see."
Further details on Henderson's condition are not available at time of writing.
Henderson has appeared just once at this World Cup, coming off the bench for the final six minutes of England's group stage win over Panama with qualification already assured.
England will now face Norway on Saturday night after Erling Haaland scored both goals in a 2-1 win over Brazil.
England's goals came from a quickfire double from Bellingham in the first half, with Kane adding their third from the spot just minutes after Quansah's dismissal.
