A club statement confirmed that David Moyes, Issa Diop and Josh Cullen have tested positive for COVID-19.
The club received the information about the positive tests while preparing for the Carabao Cup match against Hull City. The three men will now be required to self-isolate.
“The manager and both players immediately left the stadium and have returned home,” read part of the club statement.
Assistant manager Alan Irvine took charge of the Hull match at London Stadium, which the Hammers won 5 – 1. Diop and Cullen were among the starting line-up.