The Nurburgring was supposed to host this year's event as part of an alternation plan agreed with Hockenheim, but financial problems at the venue meant there was no guarantee it could fund the race.
Following weeks of talks to try to agree terms, Ecclestone has now indicated that a deal does not look like happening.
Speaking to German publication Spiegel, Ecclestone said: "After due consideration of their proposal we believe it is regrettably not financially acceptable, so we have terminated our negotiations."
The German GP's fate may now rest on Ecclestone sorting out a deal with Hockenheim, which hosted last year's race.
Should that plan not come off, then the F1 calendar could be reduced to just 18 races - with plans for a 20th event having not reached fruition.
Turkey, Austria and Portugal were all linked with that vacant slot – which has been pencilled in for July 21 – but there has been no indication of a venue getting the green light.
If Germany does not take place, then it means there will be just one race – the Hungarian GP on July 28 – between the British GP on June 30 and the Belgian GP on August 25.
2013 Formula 1 calendar