Frank Lampard has agreed on a contract at Stamford Bridge and an announcement by Chelsea is thought to be imminent after Derby County allowed him to skip the first day of pre-season to complete the deal.
Chelsea will buy out the last two years of Lampard's Rams contract at the cost of £4m ($5m) to replace their former head coach Maurizio Sarri, who joined Juventus a fortnight ago in a deal worth upwards of £5m ($6m).
The 41-year-old returns to the club where he spent 13 years, scoring 211 goals in 649 games in what is the most successful era in the club's history.
Lampard won three Premier League titles, the Champions League, four FA Cups, two League Cups and the Europa League in that time. He also came second to Ronaldinho in the Ballon d'Or of 2005.
It is understood that Lampard will bring staff from Derby with him as ex-Blues midfielder Jody Morris is expected to join as his assistant manager after working with him at the Rams.
Former Blues coach Chris Jones will also return, while head of performance analysis Steve Rands is thought to be another of the six to eight backroom staff that have spoken to the west London side.
Chelsea's Development Squad manager Joe Edwards will be promoted in line with Lampard's arrival, with the highly-rated young coach boasting a close relationship with Morris from his time in the academy.
Some of Chelsea's players will return for pre-season medical tests on Wednesday and others who have been involved in post-season international tournaments or matches are expected back at a later date after their two-week holidays.
Lampard will lead Chelsea into seven pre-season matches in Dublin, Japan, Germany and Austria before opening the season against Manchester United at Old Trafford on August 11.
However, he won't be able to request new signings due to a two-window transfer ban imposed by FIFA as the club deny wrongdoing over the signing of overseas under-18 players.
Chelsea have not asked to freeze their transfer ban by applying for provisional measures but have appealed the ban outright with a hearing not likely to be heard anytime soon through the Court of Arbitration for Sport (CAS).
Claude Makelele is expected to be returning to the club to help out with work in the loan department, while Petr Cech's return in a technical and performance advisor role has already been announced.