Danny Welbeck was forced off during the first half of Arsenal's match at Manchester City after suffering a suspected knee injury, giving England boss Roy Hodgson a potential headache ahead of his squad announcement on May 12.
The England international, who only recently returned from a long-term knee injury for the Gunners, appeared to injure himself whilst attempting to tackle Bacary Sagna in the 23rd minute of the 2-2 draw at the Etihad.
The 25 year-old forward received treatment and then tried to play on, only to walk off the pitch a minute later.
Arsenal manager Arsene Wenger suggested after the match that Welbeck had damaged the lateral meniscus fibrocartilage that surrounds the knee joint. However, the Frenchman refused to speculate on the severity of the injury.
"The first signs look like the lateral meniscus. He looks down and he's not a guy who likes to go off," said Wenger.
"I'm a bit worried. I don't want to say about the Euros - let's be a bit more optimistic."
The news will also come as a blow to Hodgson, who was expected to name Welbeck in his squad next week for the upcoming European Championships in France.
One positive for the England manager was the introduction of Jack Wilshere, who replaced Welbeck midway through the first half.
The 24 year-old midfielder has missed the majority of this season after suffering a leg fracture during pre-season.