Sheffield Wednesday manager Darren Moore is suffering from a bout of pneumonia after contracting Covid-19.
Moore had missed three games in charge of the Owls because of a coronavirus infection but returned to the dugout for the club's 2-0 defeat to Swansea City earlier this week.
"I have developed pneumonia as a result of COVID-19, with blood clots on the lungs and extreme discomfort," Moore said.
"I am gutted to be away but I understand the situation and the course of action I must take."
Wednesday have confirmed Moore suffered a setback in his recovery from Covid-19 after he oversaw their game against the Swans and say their manager will be absent from first-team affairs for the immediate future.
A statement from the club added: "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 Owls, who face Bristol City in their next game, are second bottom in the Championship and eight points adrift of safety with five matches remaining.