According to reports in the UK, Bayern Munich are ready to up their bid to £40 million for the youngster, but now they face competition from Leipzig.
While Bayern’s stature and reputation make them an obvious choice, the possibility of a buy-back is a tempting option for the Blues.
Chelsea are having difficulty tying the midfielder down to a new deal, even after offering him a new lucrative £80,000-a-week package.
The 18-year-old is set to make a decision on his future this week, with the lure of regular first-team football in the Bundesliga still tempting him with a potential move to Germany.
However, the option of Chelsea buying the player back at a later date could tempt them into letting him depart for a lesser fee to Leipzig. Bayern are not offering a buy-back clause.
Leipzig have also established themselves in Germany’s top flight, and they currently sit fourth in the Bundesliga just one place below Bayern themselves.