F1 teams likely to miss deadline
"We'll have to wait and see. I think the majority probably won't put an entry in," he said.
Toyota, champions Ferrari, Renault and the two Red Bull teams have all threatened to walk away unless the 2010 regulations, which include an optional £40 million budget cap, are rewritten.
Ecclestone doubted there would be any easy solution to a crisis that threatens to tear the sport apart and Toyota motorsport director John Howett said his team could not enter until a number of issues had been resolved.
"There is a high probability that we won't enter before the deadline because I don't think that those items will be clarified," he explained.
"If nothing changes I don't think that professionally it is possible to commit the company to do that. I can't recommend that in my position."
Ecclestone's fears are understandable given Ferrari are the biggest draw, and that their name allows him greater bargaining power with TV companies, sponsors and circuits.
"Well, I am concerned, I don't want them leaving. I don't think anybody does," remarked Ecclestone.
"We've had more than 70 teams in and out since F1 started. The only people who have been consistent are Ferrari, because they have been there from day one. So we don't want to lose Ferrari."