The Brazilian has only made eight appearances for Barca since arriving from Sao Paulo in 2014, instead plying his trade away from Camp Nou.
Despite his sparse playing time, Douglas has managed to pick up eight official titles, one for each of his appearances with the Blaugrana.
And he is venturing out once more in search of regular first-team football, this time to Turkey's Super Lig.
"FC Barcelona and Turkish Süper Lig club Sivasspor have reached an agreement for the loan of Douglas to the latter for the 2018/19 season," the Catalan club signalled in a statement.
Douglas will hope to play more in Turkey as Sivasspor look to improve on their seventh-placed finish in the Super Lig in 2017-18.
He will also be in good company, with compatriots Robinho and Auremir already starring for the club.