Mika Hakkinen, the 1998 and 1999 Formula One world champion, tested a Mercedes DTM touring car on Wednesday amid speculation that he could make a racing comeback in the German series.
However Mercedes motorsport director Norbert Haug suggested such talk remained premature.
"He has lost nothing from his speed but there is no further agreement," he said.
"Mika has been following the DTM for a long time and it was always a point of talk during our cooperation," said Haug of the 35-year-old Finn, who won his Formula One crowns with Mercedes-powered McLaren.
Hakkinen, who retired in 2001, was also linked to a possible Formula One comeback earlier in the year.
"This season Mika became a real fan of the DTM, watching it on TV, and we offered him the opportunity to test the current C class," said Haug. "This has now happened at the Lausitzring where he was driving yesterday and today."
Hakkinen's former Formula One rivals Jean Alesi and Heinz-Harald Frentzen both competed in the DTM series this year along with former F1 drivers Bernd Schneider and Italian Emanuele Pirro.
