The former-Stamford Bridge star spent four years at Chelsea as a player between 1997 and 2001, and currently manages Championship side Brighton.
But bookmakers Coral suspended betting on Poyet becoming the next Blues manager after a flood of online bets forced them to slash his price from 25-1 to 3-1.
Coral spokesman Simon Clare said: "The sudden surge of bets on Poyet suggests something significant may have gone on in the Chelsea boardroom."
And Poyet has freely admitted in the past that a return to Stamford Bridge would be tempting.
He's quoted in The Sun as saying: "The problem is Chelsea is too big to say 'no'. So I think most managers would take it anyway."
Poyet has done a fantastic job at Brighton, helping them to win promotion from League 1 in 2011, before consolidating their position in the Championship.
And his reputation as a forward-thinking, attacking young manager has led to speculation Roman Abramovich could appoint him as the next Blues boss.
The Chelsea owner appointed Rafa Benitez as interim boss earlier this season, after Champions League-winning boss Roberto Di Matteo was removed mid-way through the campaign.
But the Spaniard is only expected to stay at the club until the end of the season, with Abramovich likely to hire a permeant manager.
Long-term Chelsea target Pep Guardiola has agreed to join Bayern Munich in the summer, while former-Blues boss Jose Mourinho remains Real Madrid manager.