Toljan can play in both the left and right wing-back positions and he would be available for a cut-price deal with his contract expiring in the summer of 2018. Hoffenheim do not want to lose their talented defender but they understand that it is unlikely that he will renew.
Chelsea will likely look to use Toljan as versatile cover for current first-choice widemen Marcos Alonso and Victor Moses, though they could also consider loaning him out upon signing him in a bid for the defender to earn more experience.
Bayern Munich and Juventus have also extensively scouted Toljan, particularly as he impressed in Germany's Olympics campaign, as his side earned a silver medal in Rio de Janeiro.
Chelsea may look to further signings in the wing-back areas in the summer with the likes of West Ham's Michail Antonio, Schalke's Sead Kolasinac, Roma's Antonio Rudiger and AS Monaco's Djibril Sidibe also on their radar.
Juventus' Alex Sandro is expected to sign a new deal with Juventus, despite being linked with Chelsea in recent weeks. Bayern Munich's David Alaba has also been linked with the Premier League leaders but the German champions do not want to sell under any circumstances.