Ireland international Josh Cullen is among a West Ham trio, along with manager David Moyes and fellow Hammer Issa Diop, to have tested positive for Covid-19.
The Premier League side were preparing for a third-round Carabao Cup tie this evening, which Diop and Cullen were due to start, when the news broke.
Cullen and Diop were replaced in the starting lineup and assistant manager Alan Irvine took Moyes' place on the touchline.
West Ham confirmed the trio had returned positive Covid-19 tests and immediately left the stadium.
They said in a statement: "West Ham United can confirm that David Moyes, Issa Diop and Josh Cullen have returned positive tests for COVID-19.
"The Club’s medical team were informed of the test results as the team were at London Stadium preparing for this evening’s Carabao Cup third round tie against Hull City.
"The manager and both players immediately left the stadium and have returned home. All three, who are asymptomatic, will now follow Public Health England and Premier League guidelines and protocols.
"Everyone at West Ham United send their best wishes to David, Issa and Josh."
West Ham won the match 5-1 to go through to the fourth round. They are due to host Wolves in the Premier League on Sunday at the London Stadium.
