Theo Walcott will play no part in Tuesday's World Cup qualifier against Poland after being ruled out with a chest injury.
Walcott was injured in the opening minutes of Friday night's 5-0 win over San Marino after a collision with goalkeeper Aldo Simoncini.
He seemed to be struggling to breathe normally and was accompanied to hospital by the England team doctor Ian Beasley and kept in overnight for observation.
"Theo Walcott has been ruled out of the FIFA World Cup qualifier with Poland on Tuesday with a chest injury," the Football Association (FA) said in a statement.
"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."
While no exact diagnosis has been revealed, Walcott looked in trouble immediately after the incident, which left manager Roy Hodgson very unhappy.
"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."
With Aaron Lennon and Adam Johnson already in his squad, it seems unlikely Hodgson will call up any replacements.
But, despite Simoncini's awful challenge, for which he was lucky not to receive a red card, Hodgson refused to join the critics who claim San Marino have no place in international football.
Since they became a member of FIFA in 1990, Friday night's Wembley visitors have won just once - against Liechtenstein in 2004.
The predictably one-sided statistics showed England had 25 shots to San Marino's single off-target effort, enjoyed an 86 per cent share of possession and won the corner count 17-0.
Analysis is utterly meaningless given the pattern of play did not change from the first minute to the last and, as Hodgson observed, the most significant event of the evening was Ukraine's surprise failure to overcome Moldova in Chisinau which means England have a three-point advantage in Group H.
Little wonder TV pundit Gareth Southgate felt moved to question: "What is the point of San Marino?"
Arsenal manager Arsene Wenger's sentiments may be even more pointed once he gets a good look at Walcott.
And it is not as if a republic that covers just 24 square miles and boasts a population of 32,000 - roughly the same size as Bishops Stortford - could ever realistically show any significant improvement.
However, Hodgson is not decrying their existence as a footballing nation.
"It's up to UEFA and FIFA to decide which countries are allowed into their competitions," he said.
"San Marino have been in the Euros and the World Cup for some years.
"They play the way they play and do the best they can with the resources they have.
"We knew it was going to be attack versus defence.
"But I watched their matches against Montenegro and Moldova and it was a lot less attack against defence than our game.
"We can't accuse them of playing a dirty game of football.
"There weren't too many vicious fouls. There was one, which is the one which bothers us.
"But I wouldn't suggest they shouldn't be allowed in the competition."
It is a credit to the FA's marketing team that a crowd in excess of 84,000 turned out to watch the one-sided encounter.
Equally, Hodgson was fairly astute leaving out Ashley Cole, while also getting Michael Carrick and Wayne Rooney away from harm's way once the result had been confirmed.
With the knee injury that kept Frank Lampard out on Friday night due to be assessed when the England squad meet up again on Saturday, Carrick may well be required against Poland in Warsaw on Tuesday.
Rooney certainly will for a game Hodgson knows will be far more taxing than Friday night's affair.
"Alongside ourselves and Ukraine, Poland bear the burden of being favourites and it will be a tough game," Hodgson said.
History favours the Three Lions, who have lost just once in 17 meetings with Poland.
Another win would allow them to take a stranglehold on the only automatic qualifying spot - especially after Ukraine's unexpected stumble in Chisinau, where England scored five last month.
"I go away satisfied with the week," he said.
"We've opened St George's Park, entertained the crowd and scored five goals. And also Ukraine's result means we clawed back the two points we lost against them at Wembley last month."