Willian has flown back to London from Brazil ahead of Chelsea's scheduled return to training next week.
The 31-year-old was given permission to fly to his native Brazil in March to be close to his family after the coronavirus pandemic brought a halt to the Premier League campaign.
A number of other first-team stars, including Kepa Arrizabalaga, Pedro, Marcos Alonso, Andreas Christensen and Christian Pulisic, also returned to their home countries.
According to the Evening Standard, Chelsea have informed each of those players to ensure that they are back in London by the end of the week.
The Blues apparently hope to start an individual training programme from next Monday before stepping up to full contact on May 25, dependent on the latest Government guidelines.
Chelsea are fourth in the Premier League with nine games left to play.
