According to Kicker (h/t Football.london), Chelsea could try to sign Matthias Ginter in January. The Blues held an interest in the defender throughout the summer and it has been reported that they could return for him when the transfer window reopens.
Matthias Ginter is a 26-year-old German defender who plays for Bundesliga side Borussia Monchengladbach. He started his youth career at SC March in 1998 and spent the next 7 years in their youth setup.
SC Freiburg recruited him for their youth side as he progressed through the youth teams in the next few seasons. He was finally promoted to the senior side in 2012. In two and a half seasons, he made 81 appearances, scoring 5 goals and assisting one.
In 2014, he joined Borussia Dortmund and enjoyed a good spell there, where he won the DFB Pokal and the DFL Super Cup. He made a total of 102 appearances for them before departing for Galdbach.
Now at Gladbach, he has settled in well and is a regular fixture in the backline. So far, he has made 110 appearances, scoring 9 goals and assisting 4 (source – Transfermarkt). The centre-back has been a mainstay of the national side for a while now and has 33 appearances for them. He won the 2014 FIFA World Cup and 2017 Confederations Cup with Germany.