Nick Heidfeld is preparing to walk away from Mercedes GP as he wants a full-time race-seat for next year's Championship.
Following BMW's departure from F1 at the end of last year's campaign, Heidfeld had hoped to land a drive with Mercedes GP.
However, the team opted instead to sign Nico Rosberg and the returning Michael Schumacher, leaving Heidfeld with little option but to accept a test driver role.
And with Rosberg and Schumacher saying put next season, Heidfeld told the Bild: "With Mercedes it would not be possible to become a race driver in the near future."
The German is now looking elsewhere with Renault, Sauber and Force India all believed to be interested in signing him.
"My goal for next season is to drive again," he added.
