The Bundesliga side have secured the services of the Serbian international from BVB for the remainder of the season
Neven Subotic has left Borussia Dortmund to join Koln on loan until the end of the 2016-17 season.
The 28-year-old was poised to join Premier League side Middlesbrough in the close-season before a rib injury curtailed that move.
Subotic has yet to make a Bundesliga appearance for Dortmund this season, in part due to the injury, and his chances of first-team football at Signal Iduna Park appeared increasingly slim.
Consequently the centre-back has been allowed to leave Dortmund on a temporary basis.