The Belgian discussed a potential WRC return with Citroen team boss Yves Matton during last weekend's Legend Boucles de Spa historic event.
Duval, who won in Spa, could be back in a Citroen for a ninth outing on the Trier-based event.
"Francois is one of the three best drivers who I have met in the world championship," said Matton. "He need only show that he is motivated and he could get his chance.
"I advised him to get a copy of Rocky 3 and watch. The rally in Germany is in six months."
Duval spent a troubled season with Citroen in 2005. He won his sole WRC round with the firm in Australia that year, but was also substituted in favour of Carlos Sainz in Turkey and Greece after crashing the official Xsara WRC too often.
The 32-year-old's last WRC outing was in Germany, when he crashed a Ford Focus RS WRC off the road, in 2010. Prior to that, he had finished second in the event three times.
Citroen star Sebastien Loeb will not compete in Germany, with Dani Sordo occupying his seat in the official factory team. But that could leave space for Duval to drive the Abu Dhabi branded car used by Sordo when Loeb is present.