For their part, Napoli have already replaced Sarri with former Blues manager Carlo Ancelotti, who started the new role on July 1.
David Luiz, Alvaro Morata and Pedro were also among squad members that resumed training after going through exercises as well as stretches.More news: HIV-1 vaccine human trial shows promise
The Blues squad began their preparations for the new campaign despite the uncertainty surrounding manager Antonio Conte's situation at the club.
The 59-year-old Italian was tipped to take over from his compatriot at Stamford Bridge after Chelsea failed to qualify for UEFA Champions League football after finishing fifth.
The managerial saga has dragged on and on over the course of the summer, with Chelsea players left in confusion having already returned to their Cobham training ground for pre-season training.More news: Thai cave rescuers free three more boys
Fellow Italian Maurizio Sarri has been the main man in the frame to succeed his fellow countryman, although Sky Sports Italy have reported that negotiations between Napoli and Chelsea regarding Sarri's appointment as Conte's potential replacement are in 'deadlock'.
Stars such as Pedro, Cesc Fabregas, Marcos Alonso and Alvaro Morata who were not involved in the World Cup with their global sides reported for duty over the weekend. The West London club will not be eligible to play in the Champions League next term after missing out on a top 4 spot.More news: Hatters boss backs Three Lions to win the World Cup