Romelu Lukaku has been training at his former club Anderlecht with the 21-year-old's immediate future at Chelsea still unclear.
The Sun reports that the Belgium international was given permission by the Premier League side to train with the Belgian champions as his preseason programme with the Blues does not start until Monday.
Lukaku has spent the last two seasons away from Stamford Bridge on loan, scoring 17 goals for West Brom during the 2012-13 campaign before netting 16 for Everton last term.
Chelsea boss Jose Mourinho will reportedly give Lukaku an opportunity to prove himself during the club's preseason friendlies before deciding on his future, with his assistant Steve Holland confirming on Saturday: "The plan is that [Lukaku] will join up with us at some stage during the second week when we are in Holland."
The forward declared earlier in July that he could leave the west London side to seek regular football, saying: "I want to be somewhere where I can play my best football and hopefully win titles. It's up to me to work hard but there are choices to make. Things like that happen in football and I'm confident I will make the right choice."
Mourinho has signed Diego Costa from Atletico Madrid to lead Chelsea's front line next season, while Didier Drogba could also make a shock return to Stamford Bridge -- but the future of current Blues striker Fernando Torres is reportedly uncertain.