Over the past six weeks, the Blues have been strongly linked with an approach for the Germany international, who has been tipped to leave Leverkusen during the next transfer window.
However, with the Bundesliga outfit said to be in no rush to sell their star man, much could depend on the size of any offers made for the 21-year-old.
According to Sports Lens, Chelsea are willing to test the water with a £62m bid, significantly lower than Leverkusen's alleged £90m asking price.
While the approach could be rebuffed out of hand by Leverkusen officials, it may create a situation where the two parties can negotiate a compromise.
Leverkusen have missed out on a place in next season's Champions League, a factor which may eventually force their hand given the financial implications of the coronavirus pandemic. body check tags ::