Son has attracted the attention of many clubs around Europe following his performances last season, with Liverpool and Tottenham strongly linked with moves for his signature.
However, it appears Leverkusen have won the race to sign the talented South Korean, who scored 12 goals in 33 Bundesliga appearances for Thorsten Fink's side last term.
Kreuzer confirmed that Son’s departure from the Imtech Arena is imminent, with the club eager to get a good fee for a player approaching the last year of his contract.
"We think the transfer will go through in the next few days," he told Sky Deutschland. "I expect Son to join Leverkusen.
"You have got to look at the sporting value of the player on the one side, and the economic value to the club on the other."
The prospective deal is rumoured to be worth approximately 10 million euros, and Son's arrival at the Bay Arena outfit, who qualified for the UEFA Champions League by finishing third in the German top flight, could pave the way for Andre Schurrle to move to Chelsea.
Son's move to Leverkusen will likely to take some of the goalscoring strain off Stefan Kiessling, who finished as the Bundesliga's top scorer last season with 25 goals.