Liberty Media is waiting on progress in Miami before finalising the 2018 calendar.
It has emerged that the opening seven races on next year's schedule - every race between March and June - have now been fixed: Australia, Bahrain, China, Azerbaijan, Spain, Monaco and Canada.
And the season finale will take place on 1 December in Abu Dhabi.
"The rest of the calendar depends on whether the planned grand prix in Miami takes place," reported Auto Motor und Sport.
There are several issues with Liberty's plans in Miami, but the latest one means that a contract was not signed by a July 1 deadline set by the city.
"As of right now a contract has not been finalised," Stephanie Severino, of Miami's communications office, told Forbes journalist Christian Sylt.
If Miami's troubles can be overcome, it seems an October race date is likely, on a 2019 calendar that will once again probably host 21 grands prix.
"The conversation around 22-23 races is, I think, a few years out.
But if you put another two or three races on the calendar - a Miami, a New York, another one in Asia, some big markets - it's pretty attractive commercially to our partners," McLaren boss Zak Brown added.
