Formula One supremo Bernie Ecclestone has cast doubt on New Jersey hosting a grand prix in June 2013 despite a 10-year agreement announced last year.
"Maybe the New York race will be 2013," he told the BBC on Tuesday. "It's a when - 2013 or 2014."
The east-coast race is likely to be coupled with Canada on successive weekends and would give the United States two rounds of the championship, with Austin in Texas due to make a debut on the calendar this November if its new circuit is ready in time.
New Jersey's street-circuit race is due to be held on the banks of the Hudson river with New York's Manhattan skyline as a backdrop.
The United States, a key market for Formula One manufacturers such as Ferrari and Mercedes as well as team sponsors, has not had a grand prix since Indianapolis in 2007.
Austin had looked unlikely to go ahead until an agreement over hosting fees was reached between Ecclestone and local organisers in December.