The centre back has excelled in the Bundesliga with his calm and composed performances and his ability to bring the ball out of defence makes him a valuable asset.
The Daily Express says United were advised to scout the 22-year-old by club contacts in Germany with the Red Devils considering their options ahead of next season.
The youngster has since become a crucial player for the German side, missing only two games this season through coronavirus.
The club recently swooped to tie him down to a new contract that runs until 2026. His previous deal included a £44m release clause but that figure could now be higher.