Mason Mount has allegedly been left frustrated with Chelsea'a acquisition of Kai Havertz from Bayer Leverkusen.
Earlier this week, the Blues confirmed the arrival of the Germany international, who has penned a five-year contract at Stamford Bridge.
With Hakim Ziyech having also joined Chelsea, the presence of the 21-year-old will naturally increase competition for places in Frank Lampard's squad.
According to Bild, Mount is unhappy with two players being brought into the squad who will rival him for his role in the side.
The academy graduate enjoyed a strong first campaign in the Chelsea first team, contributing eight goals and six assists from his 53 appearances in all competitions.
However, should Lampard opt to hand an immediate debut to Havertz in Chelsea's Premier League opener against Brighton & Hove Albion in eight days' time, the Englishman could find himself out of the first XI.
