The future of the US Grand Prix will not be resolved until after this year's race on 2 July, according to officials at the Indianapolis circuit.
Just six cars lined up at the start of last year's Indianapolis race
Last season's race at the Brickyard was reduced to farce when 14 cars pulled out because of tyre safety fears.
"We had conversations after last year's event and mutually decided to address the future after we see how this year year's race goes," a spokesman said.
Indianapolis' contract with F1 expires after this year's 2 July event.
F1 boss Bernie Ecclestone has already looked at the possibility of holding a street race in Las Vegas as an alternative.
The Nevada city held a Grand Prix at the Caesar's Palace casino in 1981 and '82, but plans for a race on a street track including the famous Strip in the 1990s fell through.