Bayer revealed last week they'd rejected a stunning €25 million offer from the Blues, insisting they do not want to lose the 21 year-old. But Bayer know Chelsea won't be giving up.
The Germans have been batting away Chelsea's interest in Schurrle since snapping him up from Mainz a year ago.
Bayer swooped for Schurrle in a €10 million deal last summer, but only days later were rejecting an approach from Chelsea to sell him onto the London giants.
Bayer sports chief Rudi Voeller recalled: "Andre hadn't yet played a game for us. There was no question of us letting him go."
A year on and the Blues are back - willing to more than double what Bayer invested in Schurrle.
Voeller continued: "I phoned Andre last week on Saturday and told him that we do not want to lose him. He still has room to grow. Next season will be his year. We need him. Also: He is only 21 years old.
"(A big move) It will come soon enough, the time will come when we once again get an offer for him."
That €25 million offer wasn't rejected out of hand. Bayer's board thought long and hard about the bid. It's understood a bit of brinkmanship is in play, with directors convinced they can push Chelsea even higher for the youngster.
tribalfootball.com has learned, should Chelsea go to €30 million, Bayer will be in no position to say 'no', despite the claims of Voeller.
"The timing of the offer is all wrong. The departure of Andre makes no sense for us now. The subject is history."
Not so fast, says Mainz chief Christian Heidel.
Bayer's Bundesliga rivals would welcome such a huge deal - as they'll be due a hefty slice of the fee thanks to a sell-in clause written into last year's transfer.
"Its no big secret we would benefit if Andre was sold," smiled Heidel.
"Andre has still much room for improvement, which surely Chelsea will look at it. His first season in Leverkusen was not outstanding."
That Schurrle had an inconsistent first season at Bayer didn't surprise local observers given his meteoric rise. The Germany international only made his first team debut in 2009 and Bayer staff say the coming season, after a year adjusting to life at a club of their size and expectations, will see Schurrle produce consistently.
As Schurrle acknowledges: "I recently watched a game from my first Bundesliga season, because there are huge differences from then with the present day.
"My game has become much calmer and clearer.
"Physically, I've become more stable. I built up muscles and now weigh 76kgs. In 2009, I was 69kgs.
"I was always confident I could compete in the Bundesliga. At Mainz, I was told if I worked hard, come what may, I would succeed. That first season at Mainz was like I had been thrown into cold water. But I now do not have any doubts I belong at this level."
If Bayer had accepted Chelsea's €25 million offer, Mainz would have been due a tidy €4.5 million - a small fortune for a club of their size.
Schurrle knows all about Chelsea's interest and confesses a move to Stamford Bridge is something he's dreamed about.
In the lead up to facing the Blues in the Champions League last season, the youngster admitted they were his 'dream club'.
Those close to Schurrle, including Heidel, admit the lure of experiencing life in London is strong.
"Andre has the class to prevail everywhere," says the Mainz manager. "Including at Chelsea. In addition, London is a city where everyone would like to live."
And Heidel warns Bayer: "Bayer will have good reasons for rejecting the offer.
"But the question is: What is going on now in the forefront of Andre's mind?"