Maguire justified his selection for England’s World Cup opener with a solid display after Gareth Southgate stuck with him alongside John Stones in a back four.
But Iran striker Mehdi Taremi got the better of Maguire when he scored a late consolation goal and he immediately signaled for treatment as complained he was struggling with blurred vision.
A groggy-looking Maguire was replaced by Eric Dier as a precaution but he hopes to recover in time to face USA, when England can secure a place in the last-16 with a win.
Maguire tweeted: “I felt unwell in the second half so came off as a precaution. Looking forward to Friday.”
I felt unwell in the second half so came off as a precaution. Looking forward to Friday. 🏴 pic.twitter.com/OgEmkLGqmS
— Harry Maguire (@HarryMaguire93) November 21, 2022
Maguire and the other 10 players who started against Iran had a recovery session inside on Tuesday.
James Maddison again sat out training as he continues to struggle with a knee issue.
Southgate has allayed fears over captain Harry Kane, who left the stadium after the Iran game with strapping on his right ankle after a heavy challenge in the second half.
"I think Harry's fine," Southgate said. "It looked a bad tackle but he carried on in the game. We took him off really because we felt it was a moment we could do that.”