Theo Walcott has been ruled out of England's World Cup qualifier against Poland on Tuesday with a chest injury.
Walcott was injured in the opening minutes of Friday's 5-0 win over San Marino after a collision with goalkeeper Aldo Simoncini.
"Theo Walcott has been ruled out of the FIFA World Cup qualifier with Poland on Tuesday with a chest injury," said the Football Association in a statement.
The statement continued: "The Arsenal forward was taken to hospital following a collision with the San Marino goalkeeper on Friday night, he was monitored overnight as a precaution and following scan results today will return to his club for further treatment."
The FA are not saying exactly what the scan results showed, but coach Roy Hodgson was upset immediately after the game and suggested there might be a significant problem.
"I don't think it is going to be good," he said. "He is in hospital overnight. We can only hope it is bad bruising but he was pretty badly beaten up."
There has been no indication about a replacement being called up, although as England already have Aaron Lennon and Adam Johnson in their squad, it would be a surprise if Hodgson felt he needed anyone else.
The squad are not due to reconvene until Sunday, when Frank Lampard's knee injury will be reassessed, in addition to determining whether Ryan Bertrand has recovered from the virus that prevented him from training last week.