Alexandre Lacazette was subsituted in the first half of Arsenal's pre-season friendly against Ligue 1 side Olympique Lyonnais.
The French striker had needed attention from the physio very early in proceedings but had looked to be back on his feet, firing wide shortly after getting attention on his foot.
But on the 12th minute Unai Emery elected to substitute him for Reiss Nelson.
Lacazette had started up front alongside Pierre-Emerick Aubameyang in the Emirates Cup clash but his apparent knock gave Nelson the opportunity to show his class to fans at the Emirates.
When he originally went down it appeared to football.london 's Hugo Greenhalgh in the press box that Lacazette was simply getting some attention and more strapping to his foot but the extent of his injury is unclear at the time of writing.
Emery was expected to name a team with a mix of first-team regulars and youngsters for this game, but only Joe Willock had originaly got a chance.
Lacazette's injury gave Nelson a chance to impress on home soil as he looks to get into Emery's plans at some point in the future.
Despite Lacazette's injury seeming fairly innocuous and the bonus of seeing Nelson in action, Arsenal fans on social media were still worried about what this might mean for the rest of the season.
One user demanded a return for Danny Welbeck, while another said it 'ruined my afternoon' and another requested that Arsenal 'announce Laca is fine at half time'.
See some of the best reactions to the news below.
