The 22-year-old was the subject of a €25m bid for Chelsea last summer, and reports have claimed the Blues are set to go back in for the forward at the end of this season.
And Rudi Voller, Bayer Leverkusen director of sport, has confirmed they're open to offers for Schurrle.
Speaking to German newspaper Bild, Voller said: "It's totally normal for there to be enquiries for such a great player, even from London, and that's part of the business."
Voller's refusal to rule out the sale of Schurrle will boost Chelsea's hopes of signing the striker.
Reports in Germany have suggested Chelsea's on-loan winger Kevin De Bruyne could stay in the Bundesliga as part of a swap deal for Schurrle.
De Bruyne, currently on loan with Werder Bremen, may be used as a makeweight as part of a Schurrle transfer and German reports claim Leverkusen could be open to the idea.
Schurrle is contracted to Leverkusen until the summer of 2016, and any move from Chelsea would likely require a bid in excess of the €25m rejected last summer - unless they include De Bruyne.
Schurrle has 22 caps for Germany, scoring seven goals, and was part of Joachim Loew's squad that reached the semi-finals of Euro 2012.