Stefan Kiessling's header for Leverkusen entered the goal via a hole in the side-netting and Hoffenheim failed to recover from the blow, losing after having a penalty saved.
They return to Bundesliga action on Saturday with memories of that goal still in their minds.
"We need to try to get back to our usual routine," said coach Markus Gisdol. "Given all that has happened, that's not so simple.
"It's hard for the team to put it behind them."
The German Football Association (DFB) will meet to discuss possible consequences of that game on Monday with Hoffenheim hoping the match will be replayed.
"I think we have a big chance to send out a big message in terms of fair play," added Gisdol.
"With we, I mean the Bundesliga and Germany."
It goes without saying Gisdol did not need to show his players the incident once again as he went through the mistakes from the Leverkusen game during the week.
"Everybody's seen enough of that scene now anyway," he said. "We've tried to focus on how good we actually played against Leverkusen."
Hosts Hannover will be without midfielder Franca, who coach Mirko Slomka is looking to offload in the winter.
The Brazilian, who arrived only in January on a contract until 2016, has yet to make his debut for the Reds due to a knee injury and then illness.
"Unfortunately I think it would make sense for him if we loan him out," Slomka told the Bild newspaper.
"He's not ready for us yet."
Didier Ya Konan is also absent while full-back Christian Pander has suffered a setback in his recovery with a pulled thigh muscle complicating his return from a groin injury.