The Citizens were impressed with the 14-year-old’s development and wanted to bring him to Manchester.
But the Blues reportedly came up with a good offer that has convinced the teenager to join the Cobham Training Centre.
Sunderland’s youth academy have produced some great goalkeepers in recent years.
Everton star and England number one keeper Jordan Pickford is an academy graduate of the Black Cats. The 29-year-old made a name at the Stadium of Light before moving to the Toffees in 2017.
Meanwhile, Anthony Patterson also began his senior career at Sunderland, and now he looks to have a very bright future ahead of him.
However, Bell is poised to continue his development elsewhere as he has opted to join Chelsea.
The West London outfit have been very busy in the current Premier League transfer window.
They signed Nicolas Jackson from Villarreal for a £32 million fee, while Christopher Nkunku also arrived at Stamford Bridge in a £52m deal.
However, their transfer window is more dominated by outgoings than incomings.
They sold Kai Havertz and Mason Mount to Arsenal and Manchester United respectively. While N’Golo Kante, Kalidou Koulibaly and Edouard Mendy have all moved to Saudi Arabia.
Mateo Kovacic, Christian Pulisic, Cesar Azpilicueta and David Datro Fofana have left Stamford Bridge as well.
Meanwhile, Pierre-Emerick Aubameyang and Romelu Lukaku are also linked with an exit this summer as manager Mauricio Pochettino looks to build his own squad.