Everton's players are reportedly unhappy with their increased workload in training since Marco Silva took charge in the summer.
The Toffees have made a slow start to the ex-Hull City and Watford manager's tenure, collecting six points from their first five matches.
According to The Sun, Everton's first-team stars do not agree with Silva's approach to training, as they feel that too much work is being done ahead of games.
Certain players are said to have dropped hints with the coaching staff that they should be doing fewer hours and that the tactical setup should be made less complicated.
Silva, who signed a three-year deal at Goodison Park in the summer, takes his side to Arsenal for Sunday afternoon's Premier League clash.