The potential move marks Rafael Benitez’s attempt to add more attacking options with Fernando Torres lacking the necessary competition to lift his form, as he struggles to live up to the £50million paid in February 2011.
The versatile German international attacker has recently been in fine form with three goals in six games, including a crucial opener at the close of the first half against Schalke, creating a three-point gap between the two clubs.
Chelsea previously failed to persuade Leverkusen to part with the young German in the last transfer window, leading the Blues to consider possible contingencies if the move fails a second time.
One option is believed to be Everton’s talisman Marouane Fellaini. The reliable Belgian has notched up seven goals in twelve games so far in the Premier League after moving to Goodison Park for £15million in September 2008.
However, it will take considerable monetary persuasion for the Toffees to part with their most prized possession, whose contract ends in the summer of 2016.