The Blues secured a vital win against Arsenal over the weekend and kept a clean sheet, curtailing a concerning run of form since the start of the 2015/16 campaign.
However, the reigning Champions are still closer to the relegation zone than the top four and possess the second worst defensive record in the Premier League with 12 conceded in six games (rock-bottom Sunderland have shipped 13), and with long-serving captain John Terry, who was excluded from the starting XI against the Gunners, struggling, there are concerns at Stamford Bridge.
And reports from talkSPORT, citing L’Equipe, claim that the Londoners are looking at £7.2m-rated Cameroonian N’Koulou ahead of the winter window.
The 25-year-old is a key man at l’OM, but with his contract set to expire next summer, Chelsea are hopeful of pushing through a cut-price move.
The Blues have used French football to recruit defenders in recent times, with Kurt Zouma and Papy Djilobodji having signed for the club from Saint Etienne and Nantes respectively.