Bundesliga star underwent secret Chelsea medical

RB Leipzig Christopher Nkunku underwent a secret medical with Chelsea before the summer transfer deadline, Bild reports.

The Frenchman was heavily linked with the Blues earlier this summer, but Leipzig eventually convinced him to stay.

The playmaker put pen-to-paper on a new long-term contract, but the deal will include a buy-out clause for next summer.

It is now revealed that Nkunku underwent a secret medical with the Blues in Frankfurt with a view to a future transfer.

Nkunku is expected to stay with Leipzig this season, but there are no guarantees that he will be at the club next term.

He is already attracting high-profile interest from across Europe, and Chelsea seem determined to prise him away.

The Londoners have a superb working relationship with Leipzig, having signed Timo Werner and sold back to them.

It appears co-owner Todd Boehly is working behind the scenes to ensure that the Blues sign Nkunku ahead of their rivals.