Bayer Leverkusen have confirmed Bayern Munich were among the clubs to enquire about Kai Havertz's availability this summer.
The German champions have been heavily linked with the 20-year-old in recent months, with reports in June claiming they had made a €90 million (£82m/$100m) offer for him.
And Voller has revealed that he received several calls about the Germany international throughout the summer transfer window, including one from Bayern CEO Karl-Heinz Rummenigge.
