He signed a three-year contract last summer but he is set to become the ninth full-time boss to leave Chelsea under the ownership of Roman Abramovich.
Lampard notched a club-record 211 goals in a stellar Chelsea career from 2001 to 2014, and racked up 106 caps for England.
Juve manager Massimiliano Allegri left the Turin club at the end of the season but Premier League Chelsea wanted compensation for releasing Sarri to cover the final year of his contract.
Lampard has fared well in his first ever managerial stint with Derby county, leading them to the play-offs final.
Chelsea now can not recruit a replacement with the club serving a two-window transfer ban handed down by Federation Internationale de Football Association. Lampard would bring Chelsea academy graduate Jody Morris and former coach Chris Jones with him from Derby.
"I think he's going to rub up against certain characters at Juventus, and his tactical dogmatic nature is going to be hard when you've got so many talented players to make use for". It might be the right time for him.More news: Reggie Bullock must return after Anthony Davis trade
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Chelsea have lost their best player, Eden Hazard, they are facing a two window transfer embargo and have now fallen behind the likes of Manchester City and Liverpool.
Chelsea FC enjoyed a strong season under Maurizio Sarri, finishing third in the Premier League table and winning the Europa League under the Italian.
Juventus believe Sarri's taskmaster approach will prove the ideal follow-up after Massimiliano Allegri's departure.
Allegri had appeared on the initial list of candidates to replace Sarri at Chelsea, but has now insisted he will take a break from management, effectively ruling himself out of the Stamford Bridge running.
Italian outlet Gianluca di Marzio now report that there is "little missing" before the move can be confirmed, adding that Sarri's legal team has already met with Chelsea to discuss the specifics of his departure.