Crystal Palace manager Roy Hodgson is stable in hospital after falling ill at training, the club said.
Palace said the 76-year-old former England coach was undergoing tests amid mounting speculation he will be sacked in the coming days.
Hodgson was due to address the media on Thursday ahead of Monday's trip to Everton after a morning in which reports emerged that the club had held talks with ex-Eintracht Frankfurt boss Oliver Glasner over replacing him.
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"Following news that Roy Hodgson was taken ill during today's training session, we can confirm that he is now stable and is currently undergoing tests in hospital," Palace confirmed in a statement.
"Everybody at the club sends their best wishes to Roy for a speedy recovery."
Palace declined to comment when contacted by ESPN to verify suggestions Hodgson is set to lose his job but sources have indicated Glasner, 49, is lined up to take charge at Selhurst Park.
Hodgson was not expected to be in charge at Everton but it is currently unclear how Palace plan to proceed given the former England manager's ill health.
Hodgson is in his second spell in charge of Palace, having managed the club between 2017 and 2021 before returning for the final 10 games of last season, securing an 11th place finish and agreeing to stay on for the 2023-24 campaign.
His 200th match in charge of Palace came on Monday as Chelsea struck twice late on to secure a 3-1 win at Selhurst Park, while supporters have voiced protests in recent weeks at both Hodgson's management and the club's wider strategy after losing 10 of their past 16 Premier League matches.
Glasner has been linked with the Bayern Munich job should the Bundesliga giants dispense with under-pressure boss Thomas Tuchel.
He won the 2022 Europa League Final with Frankfurt, beating Glasgow Rangers on penalties.
Glasner is currently out of work after leaving Frankfurt at the end of last season.