The German international is a transfer target of Chelsea, who are thought to have held talks with Leverkusen over a fee for the 22-year-old.
Discussing a potential switch for the attacker to Stamford Bridge, Holzhauser has called for a quick resolution to ensure that his side have enough time to identify a replacement.
"Last year, we had an enquiry, but it came very late. This time, it is still relatively early, which is good," he said. "Andre is, alongside Mario Gotze, one of the best young players in Germany and if he leaves us, we will want cover for him. We want clarity as soon as possible."
Leverkusen are thought to want £22m for Schurrle, who has made 22 appearances at senior international level.