Mainz are counting down the final days of July.
Young attacker Yunus Malli is a target for Tottenham and his deal has a €10 million buyout clause. However, the option expires on July 31.
Malli has been linked with Spurs for much of the summer.
Mainz coach Martin Schmidt said, "Things could yet stir in mid-August.
"Some unusual offers could be made which will force us to think."