Top footballers feel unable to speak out despite Fifa ignoring their "basic needs", according to world players union Fifpro.
Alex Phillips, the general secretary of Fifpro, which represents 66,000 men's and women's players around the world, believes they are worried about potential backlash from clubs and governing bodies.
Players have raised concerns with Fifpro about their lack of rest, caused by the number of games they play - especially given this season's expanded Club World Cup.
Chelsea's final game of the season was their victory in the final of the Club World Cup on 13 July - only 35 days before the start of their Premier League campaign against Crystal Palace.