And they plan to bring him back even if they cannot persuade Guus Hiddink to replace Carlo Ancelotti.
Blues owner Roman Abramovich seems certain to axe the Italian after a trophy-less season.
Hiddink, 64, spent three months in charge of Chelsea before Ancelotti was appointed in 2009.
He is currently boss of the Turkish national team.
But the Blues believe they can lure the Dutchman back by handing the day-to-day coaching responsibilities to 44-year-old Zola.
Zola played more than 300 games for Chelsea and was voted their greatest player in a 2003 fans' poll.