The England international has had a start to the season plagued with disciplinary issues, although on the pitch his form has continued to impress.
The Blues are awaiting the verdict of their appeal to the Court of Arbitration for Sport against a transfer ban, which is due any day.
But they are already putting plans in place, and are willing to spend more than the club record £72 million fee they splashed on Athletic Club goalkeeper Kepa Arrizabalaga last year to get their hands on Sancho.
Manchester United have been regularly linked with a move for the 19-year-old, but Chelsea hope their case can be aided by Sancho’s close friendship with some of their players, including Tammy Abraham and Callum Hudson-Odoi, as well as the fact that he’s from London.
Sancho is said to be ready to leave Germany, although a report in Bild claims that a January departure is unlikely.
The teenager is seen as crucial to Dortmund's title hopes this season, having scored five goals and notched seven assists in 11 Bundesliga games so far.
The club hierarchy have therefore gone easy on him for his transgressions, which include being late for a team meeting before their Champions League clash with Barcelona last week.
Squad leaders Marco Reus and Axel Witsel were called upon to talk to the player and set him straight.
Sancho hasn’t given the impression that he is agitating for an exit midway through the season, and Dortmund will be reluctant to let one of their key players go with the title race still very much alive.
Lucien Favre’s side are currently fifth in the standings, but only five points off top spot in a congested Bundesliga table.
Sancho is likely to command a transfer fee higher than the €105 million Barcelona paid to sign Ousmane Dembele in 2017.
He has a contract until 2022 at Signal Iduna Park, and the price tag has already put off Liverpool.
United are willing to fork out a fee of up to €140 million to secure his services, but their dismal league form could make it difficult to convince the player.
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