Jurgen Klopp is contracted to Liverpool until summer 2024 after penning an extension in December.
Liverpool and Chelsea are among five Premier League clubs chasing a Dortmund defender
While other promoted sides sign players from League One, Boro conduct their business.
That would make him a brilliant bargain. Arsenal were the last team to be linked with the Serb.
Neven Subotic to Liverpool? Axel Witsel to Manchester United? N’Golo Kante to Chelsea? Probably not.