Ralf Schumacher has dropped the biggest hint yet that he will be racing for Mercedes in the 2008 DTM Championship, though the Formula 1 refugee has been advised to make his debut in a year-old car.

The former Jordan, Williams and Toyota ace tested one of the three-pointed star's C-Class machines at Estoril last month, and quickly got down to some highly respectable lap times. This week he again took to the wheel around the Portugese circuit, and suggested that his second appearance was far from merely speculative.

"I wouldn't be driving here if the DTM car wasn't a great deal of fun for me," Schumacher told German tabloid newspaper Bild. "It goes without saying, if I didn't enjoy it I wouldn't seriously consider racing in DTM.

"Now, I want to use every minute for getting to know the car. After all, I'm new to the DTM business and would have to get to know everything and used to racing the car."

The 32-year-old was dropped by Toyota at the end of the 2007 grand prix campaign, bringing the curtain down on an F1 career that had begun back in 1997 and which brought him six victories and 27 podium finishes from 180 starts.

The DTM has made no secret of its desire to welcome another star into its midst, following the departure of such as Mika Hakkinen, Jean Alesi and Heinz-Harald Frentzen over the past couple of years, and Mercedes bosses in Stuttgart have said they are expecting a decision to be made by the end of the month.

Norbert Haug, however, warned against raising expectations too high for what would be the German's maiden tin-top campaign, even suggesting that the younger brother of seven-time F1 world champion and former Mercedes driver Michael Schumacher should make his series bow in a 2007-spec machine to aid his inevitable learning curve.

"I assume a decision will come in February," the Mercedes-Benz Motorsport Vice-President told German agency SID. "If Ralf is interested then we can certainly work together.

"I'd recommend Ralf has a C-class model from 2007, which is better for learning and takes away some of the pressure. Formula 1 and DTM are entirely different, as Mika found out."

Double former world champion Hakkinen spent three years in Germany's leading touring car series, making a strong debut but thereafter producing mixed form as he struggled to adapt to the different driving style required. The Finn quit the series at the end of last season with three wins to his name.

"We aren't looking for a new Hakkinen," Haug insisted, "and we aren't interested in signing Ralf just for the headlines."