Manchester approached Hertha for a possible match in August - following in the footsteps of FC Liverpool, Real Madrid and Juventus Turin in playing friendlies against the Berlin team at the capital's Olympic stadium, the Tagesspiegel newspaper reported on Wednesday.
These games are very lucrative for Hertha, and a Manchester United team boasting international names such as Wayne Rooney and Robin van Persie would doubtless attract a big crowd.
The paper suggested this would be amplified by on-going celebrations over the news that the Berlin club will be promoted from the second league to enter the Bundesliga.
But Hertha confirmed to the paper they had rejected Man U's suggestion to play on August 6 because the date would fall too close to Bundesliga business.
That date would be the Tuesday directly after the first main round in the DFB Cup competition - and just before the start of the Bundesliga season.
As yet Hertha has no way of knowing when they will be playing their first game of the Bundesliga, but it is possible they could be called onto the pitch the day before suggested Manchester game.
The potential for a clash of dates leaving players too tired to perform well, or risking injury was considered too great, said Hertha, so they told Man U thanks, but no thanks.
Another German being wooed by the Manchester club is Jürgen Klopp, manager at Bundesliga champions Borussia Dortmund. Rumours made the rounds last week that Manchester was seriously eyeing Klopp as a successor to Alex Ferguson to manage the team.
Klopp will be at Wembley later this month to steer Dortmund against Bayern Munich in the European Champions League final.
Initial rumours about Manchester's interest in hiring him were swiftly followed on Tuesday by Ferguson's announcement that he would retire at the end of the season.