Chelsea have already made contact with Niklas Sule's representatives this summer ahead of his summer Bayern Munich exit, according to reports.
The 26-year-old will leave Bayern Munich at the end of the season when his contract expires after the club confirmed an agreement couldn't be reached between the two parties.
Bayern Munich chairman Oliver Kahn confirmed: "It took a long time and we made him an offer. He didn’t accept that offer."
Sule has attracted interest from across Europe, with a move to Newcastle United ruled out, however Chelsea remain admirers of the Germany international.
As per Adam Newson, Chelsea gave 'serious consideration' to making a £30 million for Sule last summer however opted to pursue Jules Kounde of Sevilla instead, an attempt which failed.
Now Sule's next destination unclear, with reports suggesting he is close to an agreement with a club amid interest from Chelsea and Barcelona, the Blues have already made preliminary moves this month.
football.london claim Chelsea have been in contact with Sule's representatives this month which could see the Blues 'firm up their interest' in the weeks ahead.
Chelsea could lose three defenders of their own this summer. Antonio Rudiger, Cesar Azpilicueta and Andreas Christensen are all out of contract this summer, with the club yet to agree deals.
Tuchel's side are expected to make a renewed move for Kounde this summer, but with Sule available on a free transfer Chelsea could look to swoop in.