Chelsea have reportedly started following Bayer Leverkusen defender, Jonathan Tar, with the hope of signing him as replacement for the ageing Thiago Silva.
The 27-year-old centre back has made more than 300 appearances for his club, and 21 for the German national team.
It is believed that Tah has a clause in his contract that could allow him to leave Leverkusen for a small fee— £15m.
Chelsea could do with an additional centre back at the moment, with Silva expected to leave Stamford Bridge at the end of the season when his current deal expires.
Mauricio Pochettino is also likely to lose Trevor Chalobah in January, with the 24-year-old set to leave Chelsea in search of more regular football time.
Tah is known for his pace and physicality, as well as the ability to read the game well. His positioning is also good, which is something Pochettino could use in his current squad.