Chelsea players are becoming increasingly frustrated with the workload that boss Antonio Conte is putting on them, and believe that Conte's extreme training regime is hindering their title defence.
The Times reports that Blues players think that these heavy training sessions are causing the injury problems that Chelsea currently face - with a regime of physically demanding sessions, many tactical meetings and minimal days off changing little from last season.
However, the club has the added pressure of being involved in European football, which was a burden that Chelsea didn't have in their league-winning campaign last season.
Chelsea have lost their last two Premier League matches, which has left them nine points behind leaders Manchester City, and are without four key players for this weekend's game against Watford.
The Hornets come into this weekend with an emphatic 2-1 win at Vicarage Road against Arsenal, and after an impressive start to the season currently sit two points ahead of Chelsea and a place above them.
In the current calendar there is no time for the extended breaks that Conte used to give his players, and the fatigue is starting to show. It was very evident in their Champions League game against Italian side Roma, which finished an entertaining 3-3 draw at Stamford Bridge.
Injuries are starting to take a toll on Chelsea's season, with N'Golo Kante and Victor Moses out with Hamstring injuries. Key players David Luiz and Tiemoue Bakayoko are also set to be out for a while with calf and groin problems respectively, both of which were picked up in the midweek fixture.