Still in talks, Heidfeld hopes for Mercedes seat
"I am still in promising discussions," the 32-year-old German is quoted as saying by Rheinischen Post.
"There are still teams with free cockpits and I hope I can be with a good one that can win races," said Heidfeld, a veteran of 169 grands prix but no wins.
With Nico Rosberg already confirmed for one seat, rumors are currently linking Michael Schumacher with the other.
But if the seven time world champion does not sensationally come out of retirement, it is expected that fellow German Heidfeld is the next in line.
"Whoever knows F1 knows that of those with free cockpits, Mercedes offers the best chance to be in the front," he said, admitting that he would prefer to work with an existing rather than a new team.
Mercedes GP chief executive Nick Fry said at the Motor Sport Business Forum in Monaco on Thursday that talks with "numerous drivers" are ongoing. He would not specifically deny the Schumacher rumors.