Tony Mowbray has stepped down as boss of relegated Birmingham with immediate effect, saying he needs to focus fully on his recovery from surgery.
The 60-year-old took over in January but needed a temporary break in February and then a formal medical leave of absence in March.
He has now decided to leave his post permanently after a season which resulted in the Blues suffering the drop to League One.
Mowbray said: “As people will be aware, I am currently undertaking a period of extended convalescence following significant and unexpected surgery earlier in the year which required that I take a period of medical absence…
“Over the very recent days, it has become apparent to me that I will not be fully fit to resume my duties as manager of Birmingham City in the timescale that would allow the club to best prepare for the forthcoming season and therefore, I have regrettably decided to step away from my role at this time.”
Mowbray, 60, added that he intends to return to management in the future, but wanted to “spend some quality time with my wife and my boys before I fully commit to work”.
Birmingham owner Tom Wagner said: “We are disappointed that Tony will not be coming back to lead the team forward but respect his decision to put his health and his family first.
“In a short period of time at Blues Tony demonstrated excellent leadership skills and a work ethic that galvanised all around him. He is an outstanding human being and will always be welcome at St. Andrew’s”
Birmingham took eight points from their final four Championship fixtures but finished 22nd in the table, one point shy of safety after both they and Plymouth won on the final day of the season.