Arsenal striker Danny Welbeck was forced off with an apparent knee injury during the first half of his side's Premier League game at Manchester City on Sunday.
The England international seemed to hurt his right knee in a challenge with Bacary Sagna and after receiving treatment he tried to play on, only to walk straight off the pitch and down the tunnel moments later.
It could be bad news for England manager Roy Hodgson, who announces his squad for the European Championship on Thursday.
Welbeck, 25, spent the first six months of the season on the sidelines after undergoing surgery on his left knee in September.
In better news for Hodgson, and Arsenal manager Arsene Wenger, Welbeck's replacement was Jack Wilshere, who returned to action last month after eight months out with a fractured shin.
The score was 1-1 when Wilshere came on in the 24th minute, with Olivier Giroud having cancelled out Sergio Aguero's eighth-minute opener for City.
Arsenal were already missing German playmaker Mesut Ozil due to what the club said was a "slight hip injury".