Watford defender Christian Kabasele says restarting the Eglish Premier League on June 12 would put players at risk of injury.
English Premier League chiefs are looking to get the league underway in mid-June and earlier this week voted to resume training.
But the Belgian defender now believes that the timescale given will not allow players to get back to full fitness.
"We speak about June 12," he told the Counter Attack podcast. "I think it is impossible because it would be less than three weeks' training after a long period without doing anything. It's a risk for us.
"I'm not sure, I don't have any information but I think we are not going to start June 12.
"The most obvious choice for me is the end of June. Like this you have at least four weeks to train with the team if it's possible."
At the same time, Watford defender Adrian Mariappa and two members of the club's staff tested positive for the coronavirus, while Hornets captain Troy Deeney refused to train because of fears over his family's health.
Kabasele said he understood why Deeney had opted to stay away, a decision that Chelsea midfielder N'Golo Kante has also taken.
Kabasele said the club were not putting pressure on players to return.
The English Football League will announce the first results from virus tests among Championship players on Sunday.
Second-tier clubs have carried out the tests this week ahead of their return to small-group training from Monday.