Arsenal said players will be isolated for 14 days after coming into contact with the owner of Greek club Olympiakos, who has tested positive for COVID-19.
"We are strictly following the government guidelines which recommend that anyone coming into close contact with someone with the virus should self-isolate at home for 14 days from the last time they had contact," an Arsenal statement said.
"As a result, the players are unavailable for tonight's (Wednesday's) match against Manchester City and the Premier League has decided the game should be postponed."