Chelsea are said to be in formal negotiations with Bremen over the signing of Karim Coulibaly. The defender has been a target for some time, and talks are said to be intensifying as the window progresses. The player remains under contract, but movement looks increasingly likely the longer talks go on. Chelsea are still pushing to finalise terms. However, Arsenal and Frankfurt are still watching closely and may return with offers of their own. Chelsea's back line has been a real strength this season, conceding just 1.23 goals per game (38 in 31). Karim Coulibaly would be expected to slot into that unit and hold his own in an already solid setup. Speculation continues to connect Chelsea with Joao Gomes, Nathan Ake and Maxence Lacroix while no fresh rumours surround Bremen. Stay tuned to PlayerSwitch for up-to-the-minute football transfer rumours and news from your club and beyond.