Sheffield Wednesday manager Darren Moore has revealed he has contracted pneumonia.
The 46-year-old has suffered complications, including blood clots on the lungs, following a recent bout of coronavirus.
Moore only returned to the touchline for Tuesday's Championship defeat by Swansea following a spell in self-isolation but he will now take a further period of leave.
Darren Moore has suffered a setback after his recent contraction of COVID-19 that will dictate a further absence from the club. Everyone at Sheffield Wednesday sends their very best wishes to the gaffer for a speedy and full recovery.#swfc — Sheffield Wednesday (@swfc) April 15, 2021
Moore told the club's website: "I have developed pneumonia as a result of Covid-19, with blood clots on the lungs and extreme discomfort.
"I am gutted to be away but I understand the situation and the course of action I must take."
No timescale has been put on Moore's anticipated period of absence but he will miss Saturday's visit of Bristol City.
It also seems unlikely he will be able to take charge of next Tuesday's game against Blackburn at Hillsborough.
A club statement read: "Darren Moore has suffered a setback after his recent contraction of Covid-19 that will dictate a further absence from the club.
"The Owls manager returned to Middlewood Road last Monday having completed the requisite isolation period.
"Moore felt fully fit to assume his duties but experienced discomfort following our home game with Swansea on Tuesday.
"Everyone at the club sends their very best wishes to the gaffer for a speedy and full recovery."
The relegation-threatened Owls, who appointed Moore last month, are eight points drift of safety with five games remaining following their loss to Swansea.
