It now remains to be seen whether the two clubs can agree a price to unlock the deal.
If the clubs can reach an agreement, the deal is expected to be completed rapidly, with personal terms not an issue.
While the clubs had not held formal discussions up to the current talks, Chelsea have been aware of City’s interest in Fernandez.
Chelsea set an unofficial deadline for the deal to be completed earlier this summer at a minimum fee of £120m only for that date to pass.
Fernandez could become one of the most expensive signings in Premier League history, behind only Liverpool’s £125m move for Alexander Isak last summer.
Fernandez maintains a positive relationship with Maresca, who left Chelsea in controversial fashion on New Year’s Day and moved to Etihad Stadium in June.
It could potentially be the second time City break their transfer record in the same window, having paid £116m to recruit Elliot Anderson from Nottingham Forest.
There have also been four major midfield departures, with Tijjani Reijnders sold to Saudi Arabian club Al-Qadsiah for £52m, while Barcelona have signed Rodri for £65m, Newcastle have agreed a £52m deal to sign Nico Gonzalez and Bernardo Silva departed earlier in the summer before joining Real Madrid.
It has been a turbulent period for Fernandez at Stamford Bridge, during which he and his agent, former Paris St-Germain midfielder Javier Pastore, courted interest from Real Madrid, only for the Spanish club to issue a statement denying any attempt to sign him.
The situation has been ongoing since Chelsea were knocked out of the Champions League by PSG in March, after which Fernandez became increasingly critical of the club.