The Premier League's Project Restart date of June 12 is at risk after managers reportedly asked for more time to prepare and train their players.
Footballers are due back in group training from next week ahead of a return to action next month after the season was suspended due to the coronavirus pandemic in March.
In a meeting of all 20 top-flight managers on Wednesday, concerns over the timetable were raised, and whether players will be ready for June 12 after more than two months on the sidelines, according to The Times.