Millwall manager Gary Rowett has tested positive for Covid-19 and will have to self-isolate for 10 days.
Assistant manager Adam Barrett will take charge of their Championship home fixture against Barnsley on Saturday.
Rowett woke with mild symptoms on Friday morning and did not oversee first-team training.
His positive test means he will also miss the Lions' trips to Preston on Wednesday and their home match with Huddersfield on Saturday, 31 October.
Rowett, 46, last took charge of Millwall on Tuesday when they beat Luton 2-0 at The Den and his side are sixth after winning three of their first six Championship fixtures.