Bookmakers Coral temporarily suspended betting on Gus Poyet becoming the next Chelsea manager on Wednesday following a surge of online bets.
Poyet, who is currently in charge of Brighton & Hove Albion, was priced at 25/1 before being reduced to 3/1 due to the large quantity of bets on him returning to his old club.
Coral spokesman Simon Clare said: "The sudden surge of bets on Poyet suggests something significant may have gone on in the Chelsea boardroom."
The Uruguayan played over 100 times for Chelsea during a four-year stint from 1997.