Chelsea manager Graham Potter says Reece James will see a specialist to determine the full extent of the defender’s knee injury.
He appeared to land awkwardly on his right leg and, despite briefly carrying on, succumbed to the injury on the hour mark.
Responding to the news, Potter said: “He’s due to see a specialist over the weekend.
“Until we get that information there’s not much more we can add.
“We’ll wait and see.”
Potter added: “He spoke yesterday and said he didn’t feel too bad.
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“But until you get these things checked, you don’t know.
“We’ll wait and see. There’s no point looking into the doomsday scenario yet.”
England are already sweating on the fitness of two other right-backs.
Man City’s Kyle Walker has undergone surgery on a groin problem, while Liverpool’s Trent Alexander-Arnold is out for a minimum of two weeks.
James has been in sensational form for Chelsea this season and, if fit, looks set to be Southgate’s first-choice right-wing-back in Qatar.
The Three Lions’ group opener against Iran takes place in little more than five weeks’ time.
Chelsea, meanwhile, face a run of nine games in the next month.