Chelsea have held positive talks with Maurizio Sarri in Milan and Goal understands that they remain optimistic about bringing him to Stamford Bridge this summer despite the slow progress of the deal.
Napoli have already replaced Sarri with Carlo Ancelotti but still contend they are entitled to a £7 million fee ($9m/€8m) as stipulated by a release clause in Sarri's contract.
This has complicated talks as lawyers on all three sides work on the cost, with Chelsea and Sarri hopeful that they can reduce it.
The 59-year-old still has two years remaining on his contract, but the clause helps Chelsea as Napoli president Aurelio De Laurentiis could request any fee after it expires.
Chelsea are expected to offer a two-year deal to Sarri - which would see the former Empoli coach would earn around £5 million-per-year - with the option of an extra campaign still being negotiated.
Zenit St Petersburg explored appointing Sarri but announced Sergey Semak on Tuesday as their replacement for new Italy boss Roberto Mancini , with Sarri preferring a move to west London.
Chelsea have yet to announce Antonio Conte's departure from the club and it could come at a substantial cost of around £9m, despite him having only one year left on his deal.
Conte has maintained that he intends to see out the final year of his contract , but it has been expected for much of the campaign that he wouldn't be the coach for 2018-19.
Chelsea fell short of expectations in the Premier League last season, finishing in fifth place. They won the FA Cup but will play in the Europa League next season after missing out on the Champions League on the final day of the league campaign.
Luis Enrique was Chelsea's other serious candidate for the job, but they are pressing ahead to secure the manager who brought Napoli close to winning their first Serie A title in 28 years.
