The Premier League on Tuesday revealed that six players or staff tested positive for coronavirus after the first round of testing.
Premier League tested 748 players and club staff from three clubs, though did not give out any further details.
Teams resumed training with physical distancing in mind on Tuesday after a meeting passed the decison vie video conference and tests were part of 'Project Restart' - which aims to resume matches in June.
"The Premier League can today confirm that, on Sunday 17 May and Monday 18 May, 748 players and club staff were tested for Covid-19," a statement from Premier League said.
"Of these, six have tested positive from three clubs. Players or club staff who have tested positive will now self-isolate for a period of seven days.
"The Premier League is providing this aggregated information for the purposes of competition integrity and oversight.
"No specific details as to clubs or individuals will be provided by the Premier League due to legal and operational requirements."