Arsenal boss Mikel Arteta said he was surprised the Gunners' Premier League opener with Brentford went ahead after a number of coronavirus cases at the club.
Willian is also recovering after returning a positive Covid-19 result.
Arteta said: "I was surprised but the regulations or the regulators decided the best thing to do was play."
Arteta handed debuts to summer signings Ben White and Albert Sambi Lokonga against the Bees, while forward Folarin Balogun made his first Premier League start for Arsenal.
However, the Gunners put in a disappointing performance as Brentford celebrated their return to the top tier after a 74-year absence with a memorable win.