Gunners manager Mikel Arteta will be hoping that the illness is not serious with Arsenal having suffered a number of injury and illness problems so far this season. The north Londoners sit bottom of the Premier League after three games.
U21s manager Lee Carsley has confirmed that the incident is not related to coronavirus after the Young Lions saw a friendly in Romania cancelled following an outbreak in their camp.
Carsley has been preparing his side for his first game in charge against Kosovo on Tuesday night, but lost a key man in Smith Rowe.
“It’s not Covid related,” Carsley told Sky Sports. “He was just feeling unwell so we decided to send him back to Arsenal.
“He didn’t feel 100 per cent so the best thing to do for Emile was to send him back.”
Cole Palmer replaced Smith Rowe in the starting XI with another Arsenal man in Folarin Balogun named on the bench.
There will be concerns in north London now that Arteta will not be able to call on Smith Rowe, who signed a new deal recently, in their Premier League fixture against Norwich.