Head coach Thomas Tuchel had reportedly accused Romelu Lukaku of being overweight in the days before his well-documented interview about his future.
Last Thursday, Sky Sport Italia broadcast comments from the Belgian which insinuated that he was keen to return to Inter Milan at the earliest opportunity.
The matter has since been resolved with the summer signing starting Chelsea's 2-0 victory over Tottenham Hotspur in the EFL Cup on Wednesday night.
However, according to Football Insider, the catalyst for the saga was Tuchel making enquiries over a perceived lack of sharpness from the club's record signing in comparison to his days at San Siro.
The report claims that the 28-year-old weighed is between 3kg and 8kg heavier than he was at Inter, a period which includes when Lukaku was sidelined with an ankle injury.
Lukaku has made a total of 13 starts and six substitute appearances since returning to Stamford Bridge in the summer.
