The Grêmio star was a key member of the Corinthians side who acheived promotion in 2008, moving to the Middle-East, before returning to Brazil with Grêmio in 2012.
The Porto Alegre club were desperate not to lose their star, but have admitted that with Douglas soon able to negotiate a pre-contract out of the club, their hand was forced over the move.
Corinthians will pay €1.3 million for the attacking midfielder, whilst the player will earn a big pay rise up to €45k a week.
