Sunderland have been hit by a Covid-19 outbreak at the club's training ground.
It means eight first-team players will miss tonight's League One game with AFC Wimbledon.
A club statement read: "Sunderland will be without eight first-team players this evening following an outbreak of Covid-19 at the Academy of Light.
"After displaying symptoms of coronavirus on Sunday, one senior player has returned a positive test for Covid-19 and is currently observing a period of isolation.
"In line with Government advice, seven other first-team players are also self-isolating at home – two of which have displayed symptoms – after coming into close proximity with the individual that has tested positive.
"Due to the severity of the impact this has had on the team’s preparations for Tuesday’s match, the club explored the option of postponing the fixture and engaged in extensive dialogue with the EFL.
"Disappointingly, an agreement couldn’t be reached due to the lack of clarity regarding potential sanctions SAFC could face in the event that the fixture was unfulfilled.
"The club introduced wide-ranging protocols to protect its players and staff following the initial outbreak of coronavirus in the United Kingdom in March, including the closure of the Stadium of Light and the Academy of Light.
"Since returning to training ahead of the 2020-21 season, SAFC has continued to follow these comprehensive protocols to the letter and adhered to all of the latest advice and guidance provided by the Government and the EFL.
"The club will not be naming individuals who are currently self-isolating and asks that their privacy is respected."
