Chelsea have agreed to sell Oscar to Chinese club Shanghai SIPG for a fee of around £60m.
The Brazil midfielder will leave Stamford Bridge when the transfer window opens at the start of January.
Oscar, 25, who joined Chelsea in 2012, went on to win the Premier League, Europa League and League Cup with the club.
Since Antonio Conte took charge at Stamford Bridge, Oscar has featured just 11 times but the Blues manager said this month he was sad to be losing a player who scored 38 goals in 203 appearances.
“Oscar is a really good player,” Conte said.
“A good player. For me, I was very proud to have him in my squad and have him as my player. I’m proud of his attitude, his commitment and his behaviour, which have been fantastic.
“I have great respect for every decision made by a single player. If you ask me, ‘are you sorry?’, then yes, I am sorry. I must be honest about this. But, also, I understand him and his decision.”
Oscar’s manager at Shanghai will be former Chelsea boss Andre Villas-Boas.
Nigeria’s Mikel Obi, who has been frozen out of the Chelsea squad since Conte’s arrival, is also been tempted by the Chinese club.