"Russia is a highly significant market for the DTM and for Mercedes-Benz," Wolff said at the time.
However, he made no mention of Russian Petrov's chances of actually securing a race seat for 2014.
Wolff told Russia's f1news.ru website that the 29-year-old was predictably "fast" in the test.
"Vitaly has been on the podium in formula one. What else do you need to say?" said the Austrian.
"The test was successful, and now we are trying to bring everything together to sign a contract.
"We are considering the option (of signing Petrov) very seriously," added Wolff. "If you want me to be specific, I would say the chances are about 60 per cent."