The governing body of Europe's top leagues says it is "impossible" to know when football will be able to resume.
Most European leagues have been suspended indefinitely as a result of the coronavirus crisis and Alberto Colombo, the deputy general secretary of European Leagues, is certain any restart will take place in empty stadiums.
"The priority so far has been on focusing on creating conditions to be able to resume competition during the summer should we be able," Colombo told BBC Sport.
"You need to resume training and develop your own protocols. There's no doubt it will be behind closed doors, so the competition organisers have to develop medical protocols, training protocols, match-operation protocols.
"But, of course, it's impossible to answer the question 'when we will be back playing?' Nobody has these answers."
It has been reported that a number of Premier League clubs will seek a cut-off to the 2019-20 season of July 1 in Friday's shareholders' meeting.
While it is understood the Premier League is reluctant to commit to any firm decisions until the Government puts a plan in place to lift lockdown measures, clubs are said to be wary of the campaign dragging on.
- TEAMtalk media