Preston North End have confirmed striker Jayden Stockley was one of 10 positive Covid-19 tests across eight Championship clubs in the latest round of testing.
There were also seven positive tests confirmed in League Two.
A total of 1,058 tests were carried out in Championship clubs on Thursday and Friday; four clubs and 135 individuals took part from League Two.
All of those who tested positive will begin a period of self-isolation.
Middlesbrough and Cardiff have each confirmed one positive test from the most recent round of testing.
There is no programme of testing for League One at present.
There were no new positives from the latest round of testing in the Premier League on Thursday and Friday.
Preston’s Stockley, 26, is described by his club “asymptomatic and feeling no ill effects”.
“It came as a complete shock. I got a call from the doctor when I came back from training,” said Stockley.
“I felt brilliant in training, put a good session in and his number came up. We were aware we would get a call if our test was positive and I was thinking ‘no, surely not’, but he told me and it was a surreal moment.
“You feel like you are untouchable and you are going to ride through it.”
The four League Two clubs involved in the latest round of testing were Exeter, Cheltenham, Colchester and Northampton, who occupy the four play-off berths. Teams in League Two have already indicated they wish to end the season but the promotion play-offs are expected to go ahead.
Colchester say four people tested positive at their club, while Northampton confirmed their physiotherapist Ignacio Herrando was their only positive test. Herrando is described as “asymptomatic and feeling no ill effects”.
Exeter returned two positives and Cheltenham none.
Blackburn captain Elliott Bennett and two unnamed Fulham players tested positive for coronavirus in the previous round of testing in the Championship.
Two people at Hull were confirmed to have the virus after the first round of testing.