England defender Danny Rose says players are being treated like "lab rats" after Watford and Burnley revealed they were among the English Premier League clubs affected by six positive tests for the coronavirus.
Teams have started socially-distanced training in small groups this week, but several Premier League stars have expressed concerns about plans to resume the season.
The Premier League conducted 748 tests on players and staff on Sunday and Monday as part of their bid to restart matches in June.
Burnley assistant manager Ian Woan, one unnamed Watford player and two members of the Vicarage Road staff tested positive in the first batch of medical checks.
While the positive test numbers were relatively low, Rose joined Watford captain Troy Deeney in speaking out about the potential health risks of pressing ahead with "Project Restart".
"People are suggesting we should go back to football, like we're guinea pigs or lab rats. We're going to experiment this phase and see if it works or not," said Rose, currently on loan at Newcastle from Tottenham.
"I can just imagine people at home saying, 'Well they earn that amount of money so they should be going back'. For stuff like that, is it worth the hassle? I could be potentially risking my health for people's entertainment and that's not something I want to be involved in."
Deeney refused to start training because he does not want to put his young child, who has breathing difficulties, at risk of catching the virus. The 31-year-old had already made it clear he fears his family could be in danger because of figures that show black and ethnic minorities are more likely to become seriously ill with the virus.
His decision came just hours before Watford released information about their positive tests.
The Premier League has been suspended since March 13, but it is hoping its remaining 92 matches can be played behind closed doors.