England midfielder has contract terminated at the Stadium of Light.
Adam Johnson did not manage to get on the pitch during Sunderland's 1-0 win over Crystal Palace.
Sunderland lost at home 1-0 to Southampton on Saturday.
Adam Johnson has made just six Premier League appearances for Sunderland this season.
The returning winger failed to inspire the Black Cats against Manchester United.
The former England international is nearing a return.
The Dutchman is pleased with his options in attack after a busy summer.
Dick Advocaat faces a selection poser ahead of trip to Bournemouth.
Sunderland manager Dick Advocaat is in an optimistic mood ahead of two bigs for the club.
Dick Advocaat has an uphill task to keep Sunderland in the Premier League, and must pick up his first points against arch rivals Newcastle on Sunday.