Mercedes motorsport competition director Norbert Haug said on TV after the last DTM race, that he asked Villeneuve to come, whenever he has time, and have a test run in the DTM car. And that it would be a nice addition to have him racig in the DTM and for Mercedes. And he was interested bla bla etc.
So maybe we will see him there someday, as Ralf Schumacher also ended in the DTM after a test run in the Mercedes car.