Gonzalez scored the goals to fire Stuttgart up to the Bundesliga this season, but he is pushing to now leave the German side in the ongoing transfer window.
The striker is an attractive proposition for a host of clubs, including Premier League new boys Leeds, but Stuttgart are not keen to sell.
Stuttgart head of sport Hitzlsperger believes clubs are willing to put big money on the table for Gonzalez and insists to convince his side to sell they will need to do just that.
“With him you can imagine that clubs are willing to spend a lot and they have to”, he was quoted as saying by German outlet TAG24.
“If we decide to hand him over, then it really has to be expensive.”
It is claimed that Stuttgart are looking for around €20m to let the Argentine striker move on before the transfer window closes in October.
And Hitzlsperger insists Stuttgart will also need to replace Gonzalez if he does go.
“If you give up quality, then you have to adequately replace it”, he said.
Gonzalez scored 15 goals for Stuttgart across all competitions last season.
