A friendly between Manchester United and Stoke was called off at the last minute after the manager of the Championship side, Michael O'Neill, was diagnosed with coronavirus.
Stoke had arrived at United's Carrington training base on Tuesday and were in the academy building when they found out.
"Stoke City can confirm that manager Michael O'Neill has tested positive for the Covid-19 virus following the latest round of testing on Monday (June 8)," read a club statement.
"O'Neill had tested negative in the previous five rounds of testing.
"He will now follow the relevant guidance and undergo a period of isolation, whilst continuing to be in regular virtual contact with his coaching staff and players."
O'Neill's assistant Billy McKinlay will prepare the team for their game with Reading on June 20 when the Championship resumes after being suspended in March due to the pandemic.
Stoke are just three points above the relegation zone with nine games remaining.
O'Neill tested positive for coronavirus after testing negative on five previous occasions