Formula 1 chief Bernie Ecclestone says the 2013 calendar could still include 20 races, with France and Portugal showing interest to host the event.
The calendar was modified by the FIA at the end of last year to make room for a European race on July 21.
Venues like the Red Bull Ring in Austria or Istanbul in Turkey were linked to the slot, but their chances seem to have evaporated and Ecclestone said in December that he expected the calendar to include just 19 events.
Ecclestone now says talks are still ongoing about a possible deal to have 20 races, and revealed the Algarve circuit in Portugal has now entered the frame.
"To be honest, I don't know," said Ecclestone when asked about plans for the July 21 slot.
"There is interest still in France, and now also in Portugal. They want to do it at the new Algarve track.
"For Germany, it would be Nurburgring. Let's see if they can put it together."
Ecclestone admitted, however, that the race was unlikely to be added to the calendar as Formula 1 teams were not keen to have an extra GP.
He added: "If someone wants to have the 20th race, it will happen, if the track is there and okay. We can help [with] organising.
"However, the teams do not seem to be in favour of this race. I doubt it will happen."
The Briton also insisted the calendar will not be expanded beyond 20 races in the future, despite several countries wanting to join.
"No. Twenty [is] the maximum amount," he said.