Mason Mount is reportedly unhappy with the arrival of Kai Havertz at Chelsea which is set to reduce his game time at Stamford Bridge.
The Blues completed a deal for the £89million-rated Bayer Leverkusen forward this week as part of Frank Lampard's £230million transfer spending spree this summer.
Havertz's arrival is likely to provide extra competition in attacking midfield for Mount, who played in every single Premier League game bar one for Lampard's side in his debut season in the top-flight.
And according to German news outlet BILD, the 21-year-old is not pleased at Chelsea making a new mega-money signing for a player in his position.
Havertz is capable of playing anywhere in the front three but it is believed the attacking midfield role is where Lampard will place the German international in his new-look Chelsea side.
The Blues have also invested in the striker and wide positions this summer with the arrivals of Hakim Ziyech and Timo Werner from Ajax and RB Leipzig respectively.
And Havertz's arrival means the west Londoners have a new attacking line-up ready to take on defences next season and the former Leverkusen man is currently looking for houses in the London area following his move.
Mount's end-of-season form for Chelsea, meanwhile, earned him a place in Gareth Southgate's England squad for the September internationals against Iceland and Denmark, but the 21-year-old is looking to maintain this level with the European Championships taking place next year.
The Chelsea midfielder has also seen the likes of Kalvin Phillips, Phil Foden and Ainsley Maitland-Niles break into the Three Lions squad for the first time this month, meaning there is even more competition in central midfield at international level.
Mount was trusted by Lampard throughout the campaign having impressed the Chelsea legend on a loan spell at Derby County during the coach's first season in management.
He was fast-tracked into the Chelsea first-team and made 53 appearances in all competitions last term.
The Englishman signed a new five-year contract at Stamford Bridge in the middle of July and is expected to be a regular name on the Chelsea teamsheet in the years to come.