Gabriel Martinelli was substituted partway through Arsenal's Carabao Cup quarter final meeting with Manchester City after receiving a heavy blow to his right foot.
The Brazilian was making his first start since recovering from an knee injury which kept him out for the majority of last season.
Just before half time he went down in some pain after receiving a late tackle from City goalkeeper Zack Steffen, immediately crying out and pulling his shirt over his head. He received treatment for several minutes but after limping off he managed to rejoin the fray.
However, after being involved in another challenge early into the second half, he again went down with Nicolas Pepe replacing him in the 49th minute. Martinelli did at least leave the field of play under his own weight and did not disappear down the tunnel for additional treatment, which suggests the injury should not be that bad.
His absence would be a big blow to the Gunners as prior to being taken off he had been playing well. Martinelli looked spritely both on and off the ball and even provided the assist for Arsenal's equaliser. Getting into a promising position down the left hand side, he swung in a great cross which was converted by Alexandre Lacazette.
The goal levelled things up after City had taken the lead inside two minutes through Gabriel Jesus. The goal featured a terrible defensive mixup involving Shkodran Mustafi, Gabriel and stand-in goalkeeper Runar Alex Runarsson.
Arsenal's stopper would make another error for City's second goal when he let Riyad Mahrez's free kick squirm through his hands. The visitors then made it 3-1 through Phil Foden, who produced a fine finish just before the hour mark.