Arsenal midfielder Emile Smith Rowe suffered an injury during the Gunners' post-match warm-down after losing 3-1 to Manchester United on September 4 as per The Athletic.
Bukayo Saka's second-half equalizer wasn't enough for Mikel Arteta's side as a Marcus Rashford double and a debut goal for new signing Antony secured a win for United.
Smith Rowe came on in the second half for captain Martin Odegaard in the latter stages but he couldn't have a significant impact.
The young English attacker appears to have now suffered an injury as he pulled up with an issue during Arsenal's warm-down session.
The former RB Leipzig loanee was helped to the dressing room by assistant coach Carlos Cuesta.
The extent of the injury remains to be seen, but if sidelined he would become the latest absentee for the north London side.
Thomas Partey, Mohamed Elneny and Reiss Nelson are already on the injury list for the Gunners.
It has been a somewhat difficult start to the season for Smith Rowe as he is being kept out of Arsenal's starting XI by Odegaard.
He has featured in four of the Gunners' first six fixtures of the campaign, being handed just 47 minutes of action.
The English attacker can also play as a left winger, but that role has been given to Gabriel Martinelli.
The young Brazilian has formed a formidable front three alongside Gabriel Jesus and Bukayo Saka.
Arsenal to bounce back against FC Zurich
Next up for Arteta's men is a trip to Switzerland to face FC Zurich at the Stadion Letzigrund in the UEFA Europa League.
The Gunners are being touted as frontwinners to win the competition and will want to kick their tournament off with a win.
Sunday's defeat to Manchester United comes as a blow as the north London outfit had been the Premier League's in-form team.
A first loss of the season may affect the side's mood but Arteta is confident his side will bounce back given the performance.
He told the club's official website:
"The personality of the team showed, the way we dominated the game, the way we imposed ourselves in the way we wanted to play. That has to be backed up with a result. That’s the disappointment today.”
He added:
“We put so much into this game and are really pleased with the effort and the quality the boys showed today but we need to move on to the next one.”