Darren Moore is suffering from pneumonia following his recent contraction of COVID-19.
Manager Moore felt fully recovered from coronavirus after the requisite isolation period, returning to touchline duties on Tuesday for the Swansea defeat.
However, he experienced discomfort following the game and has confirmed he has been diagnosed as having pneumonia.
Moore told swfc.co.uk: “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.”
The club said: “Everyone at the club sends their very best wishes to the gaffer for a speedy and full recovery.”
First team coach, Paul Williams, has also been absent from the club after contracting COVID-19.
On the field, we take on Nigel Pearson’s Bristol City at Hillsborough on Saturday lunchtime, now eight points from safety following Coventry’s win at Rotherham tonight, and with just five games remaining.