Vincent Kompany was taken to hospital after collapsing at Bayern Munich's training ground on Friday.
Kompany's condition is said to be stable, according to Sky in Germany.
"Vincent Kompany had to seek medical treatment on Friday after collapsing during training for FC Bayern's amateurs," said the club in a statement.
"The first-team coach had been watching the second team's session. Kompany will undergo thorough examination in the hospital and remain in medical care. For the time being, his coaching staff will manage training and match operations."
Director of sport Max Eberl added: "Vincent Kompany's health is our top priority. We at FC Bayern will do everything we can to ensure he makes a speedy recovery.
"Vinnie is receiving all the necessary medical care and support, and all the time he needs. His coaching team, in whom we have complete confidence, will take over his duties. All of us at FC Bayern wish Vinnie a speedy recovery."
Kompany's former club Manchester City also sent their best wishes, with a post on their X feed reading: "Everyone at Manchester City is wishing a speedy recovery to our former captain and club legend, Vincent Kompany.
"Get well soon, Vinny."
The Bayern head coach has been suffering from a viral infection of late and was unable to attend his side's pre-match presser ahead of the midweek Champions League game against Arsenal at the Allianz Arena.
Kompany was well enough to take his place in the dugout though for the 2-2 draw against the Gunners on Wednesday.
Bayern face Freiburg in the Bundesliga on Sunday.
