With Premier League clubs on course to restart the season next month, doubts have been voiced by some players about taking the field during the coronavirus outbreak.
On Wednesday, 20 clubs received clearance from the British government for players to work together as a squad as restrictions are eased across England.
Players and staff members at clubs are being tested twice a week for COVID-19 with four individuals from three clubs now testing positive in the latest round of testing.
"The Premier League can today confirm that on Monday 25 May and Tuesday 26 May, 1008 players and club staff were tested for COVID-19," the league said in a statement.
"Of these, four have tested positive from three clubs.
"Players or club staff who have tested positive will now self-isolate for a period of seven days."
However, players still have reservations about playing - particularly at Watford - who sit is a place above the relegation zone.
"I'm not in favour of the Premier League returning, in a sense that not everyone is comfortable with it," Watford backup goalkeeper Heurelho Gomes said.
"I believe the virus isn't going away from one day to another. We obviously hope it does, but the problem will remain until a vaccine is developed."
Watford captain Troy Deeney did not return to training last week over concerns about his son's health.
"Some players need more time, and that can be a disadvantage to some smaller clubs as they don't have too many replacements," Gomes said.
"We should only return when everyone is cool about it and we have more time for training and adapting."
Clubs will hold another conference call on Thursday to discuss plans to resume the season in the second half of June, including the scheduling of games that will all be closed to fans.
The location of matches is still to be resolved after clubs rejected proposals for all fixtures to be played in neutral venues.
But there are still contingencies being formulated if there is a need to abandon the season, which was suspended in March with Liverpool leading by 25 points with nine games remaining.
For now, the teams are trying to get the players match fit after an unprecedented time away from the sport.
After working in smaller groups and avoiding contact since training resumed last week, players can now enter the next phase to step up preparations for games. The protocols still acknowledge the social distancing required in wider society.
"Squads are now able to train as a group and engage in tackling while minimising any unnecessary close contact," the Premier League said in a statement.
Germany's top division restarted on May 16 and Spain has government approval for games after June 8. England's resumption will only come later in the month.
"Discussions are ongoing as work continues towards resuming the season," the Premier League said, "when conditions allow ... when safe to do so."
Australian Associated Press