Watford defender Adrian Mariappa says he is one of three people who tested positive for coronavirus at the club.
On Tuesday, it was announced there had been six positive tests across three Premier League clubs.
Two staff at Watford and Burnley assistant manager Ian Woan also tested positive, while the two others at a third club have not yet been revealed.
Chelsea's N'Golo Kante missed training over coronavirus fears, with the backing of his manager Frank Lampard.
Kante's decision to train at home follows a similar stance by Watford captain Troy Deeney and several of his team-mates.