The 22-year-old, who has scored nine times this season for the Bundesliga side, is known to be on the radar of the west London club - in a reported €22 million deal including a loan move for Kevin De Bruyne in the opposite direction.
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Voller told Deutsche Presseagentur: "We are receiving transfer enquiries every now and then.
"Andre Schurrle is not the only player of interest. It is obvious to have a look at those proposals. We also did that last summer."
Meanwhile, executive Wolfgang Holzhauser expressed his annoyance at the continual speculation surrounding one of the club's star assets.
He told Reviersport newspaper: "At this point in time, there is so much said. There are many rumours. I would prefer not to be part of all this."