Nigeria international Alex Iwobi could miss Arsenal FC's encounter with Spanish giants AtletIco de Madrid.
The two teams will lock horns in the 2017/18 UEFA Europa semi-final second-leg match in Madrid on Thursday.
Iwobi, 21, played the entire game as Arsenal lost 2-1 to Manchester United in an English Premier League game over the weekend.
Arsenal manager Arsene Wenger has since disclosed that Iwobi, Henrikh Mkhitaryan and David Ospina are all nursing injuries.
“Mkhitaryan I took off because he had a little knock on his knee again," Wenger said on Goal.
"The same thing, just looking at him in the dressing room.
“Ospina has a rib problem and Alex Iwobi has a hamstring problem," he added.
"We’ll see how everyone recovers because Thursday will come around very quickly.”
Arsenal and Atletico 1-1 in the first-leg clash in London last week Thursday.