Chelsea are attempting to steal a march in the race to sign the prolific and versatile 24-year-old Frenchman.
Sources said the Blues have ‘done everything’ as part of their groundwork on the proposed deal to leave themselves well-placed in the race to land Nkunku, and they will continue their efforts to finalise a transfer, says the Daily Mail.
Nkunku has already had medical checks in Frankfurt during the summer with a Chelsea orthopaedist present.
Chelsea are also understood to have discussed personal terms with Nkunku as part of their attempts to convince him to join. The player confirmed his interest in response.
Nkunku was a wanted man in the summer after a stunning breakout season.