West Ham United manager David Moyes and players Issa Diop and Josh Cullen have returned positive tests for COVID-19, the Premier League club said on Tuesday.
The club's medical staff were informed of the test results as the team were preparing for Tuesday's League Cup third round match against Hull City at London Stadium.
"All three, who are asymptomatic, will now follow Public Health England and Premier League guidelines and protocols," the club said in a statement, adding that the manager and both players immediately left the stadium and have returned home.
The club statement added that West Ham had offered to conduct COVID-19 tests for the Hull City team before the match but the visitors declined.
French defender Diop and Ireland midfielder Cullen were replaced by Harrison Ashby and Jack Wilshere respectively in the starting lineup around 45 minutes before kick-off.
The match started as scheduled at 1930 BST with assistant manager Alan Irvine taking charge of West Ham.
Atletico's Gimenez tests positive for COVID-19 -club statement
Atletico Madrid defender Jose Gimenez has tested positive for COVID-19, the La Liga club said on Tuesday.
The Spanish club's statement said that Uruguay international Gimenez, who returned a positive result on Monday, is isolating at home in accordance with the health authorities' guidelines.
Earlier this month, Atletico coach Diego Simeone also tested positive for the novel coronavirus.
Atletico, who finished third in the league last season, begin their new domestic campaign at home to Granada on Sunday.