Chelsea are unhappy with Celtic for the treatment of young attacker Charly Musonda, who moved to the Scottish Champions in a 18 month loan deal in January.
According to the Daily Mail, the Stamford Bridge club are said to be alarmed that Brendan Rodgers has only handed the 21-year-old Belgian two starts since his move North.
The former Swansea and Liverpool coach previously worked as a youth coach at Chelsea and has used his connections with the club to secure loans for both Josh McEachran (Swansea) and Victor Moses (Liverpool), although both these players also struggled for regular game time under his guidance.
Rodgers has done a fine job since taking over at Celtic in the summer of 2016, winning the Scottish Premiership in both of the last two seasons.
The 45-year-old has even been mentioned as a replacement for Antonio Conte when the Italian coach departs Stamford Bridge at the end of the season, although it is doubtful that Chelsea’s board will be too impressed with his record of helping develop their young players.