The German centre-back has long been hailed as one of the best players in his position in the Bundesliga and helped his nation to lift the World Cup in 2014.
It was after this feat that Manchester United trailed the now 27-year-old, but Louis van Gaal’s side were unable to prise him from BVB’s grasp.
However, reports claim that Chelsea are now attempting to do so, with a tentative early approach having been made.
With John Terry looking likely to leave the club this summer as his contract ticks towards its expiration, Hummels could become the main man in the Londoners’ defensive ranks under their new boss – likely to be Antionio Conte.
The Dortmund hero has often been lauded for his ball-playing style from the back, but is also known for his impressive all-round defensive game.