West Ham manager David Moyes and two club players have tested positive for the coronavirus.
The Premier League club, reports the BBC, was informed of the positivity just before the start of the third round of the League Cup against Hull City at the London Stadium, scheduled for tonight.
Moyes, 57, defender Issa Diop, 23 and midfielder Josh Cullen, 24, will have to be placed in solitary confinement.
"The coach and both players immediately left the stadium and returned home," said the club, stating that the three are asymptomatic.
Assistant coach Alan Irvine took charge of the match against Hull, in which both Diop and Cullen would play as starters.
British public health guidelines state that Covid-19 sufferers must self-isolate for at least 10 days, which means Moyes, Diop and Cullen will not be able to participate in training or the championship match against Wolverhampton on September 27.
Another League Cup match, between Tottenham and Leyton Orient, has been postponed due to Covid cases within the Leyton squad.