Leipzig are due to host Spartak Moscow in the first leg on 10 March, with the second leg scheduled for 17 March. But those matches would not hold following Russia's invasion of Ukraine.
The European governing body UEFA confirmed on Monday that they are placing an indefinite suspension on all Russian football clubs including the national teams.
Also, German's transport ministry said at the weekend that it was closing its airspace to Russian planes and airlines for three months. Russia calls its actions in Ukraine a "special operation."
"We continue to be in close contact with the associations and have complete confidence in UEFA and their decision. We assume the games will be cancelled," Mintzlaff said in a statement on Monday.
Last week, UEFA said the home games of Ukrainian and Russian club and national teams competing in UEFA competitions would be played at neutral venues "until further notice" but now the games would not hold at all.
Although it remains to be seen if they would lose out on their places in on-going competition or the matches will be postponed.