Newcastle boss Eddie Howe thanked fans for the "messages and warm wishes" after the club announced he is recovering in hospital after being diagnosed with pneumonia.
Howe, 47, went to hospital late on Friday having felt unwell for a number of days.
Newcastle said on Saturday he would be absent for the Magpies' Premier League match against Manchester United at St James' Park on Sunday, which they won 4-1.
"A huge thank you to everyone connected with Newcastle United and the wider football community for your messages and warm wishes. They have meant a lot to me and my family," Howe said in a statement issued by the club.
"I also want to pay tribute to our incredible NHS and the hospital staff who have treated me.
"I'm immensely grateful for the specialist care I'm receiving and, after a period of recovery, I look forward to being back as soon as possible."
Jason Tindall and Graeme Jones will lead Newcastle for their forthcoming matches against Crystal Palace and Aston Villa.
The club said "further updates" concerning Howe's situation would be "communicated in due course".