Reports in England have claimed the Brazil international is set to reunite with former manager Andre Villas-Boas after Chelsea accepted an offer said to be worth up to €60million.
And the 25-year-old is now expected to complete the move when the transfer window opens after claiming that the deal is all-but finalised.
"It's 90 per cent certain," he is quoted as telling SporTV. "It just depends on a few bureaucratic details."
Oscar has won the Premier League, the Europa League and the EFL Cup since joining Chelsea from Internacional back in 2012.
The attacking midfielder was a key part of former boss Jose Mourinho's plans, particularly during their title-winning campaign of 2014-15, but he has found his opportunities limited under Antonio Conte.
Oscar started all five of Chelsea's opening Premier League games this season but has been restricted to just four substitute appearances since September, with Conte having revitalised his side's form during that time by using a 3-4-3 system.
He is expected to become the most expensive signing in CSL history, with his transfer fee anticipated to eclipse the reported €55.8m paid by Shanghai to sign compatriot Hulk from Zenit in June.