Speculation that this year's Formula 1 calendar will shrink from its current 23 races looks to be accurate.

Toto Wolff said recently he expects the 2021 schedule might ultimately be "shorter" due to covid-related cancellations, and now Carlos Sainz agrees.

"Everything changes every week," the Ferrari driver said.

"Perhaps it's time to get used to constant changes like this for the next couple of years. At the end of the day we cannot choose which tracks we go to."

It now appears likely that, with Melbourne and Suzuka recently called off, only one of those two races will ultimately be replaced.

F1 CEO Stefano Domenicali admitted that Qatar is the likely replacement.

"Yes, it is correct, there have been talks," he said at Spa.

"But I cannot confirm anything or deny anything at this stage because it would be wrong from my side."

The buzz in the Spa-Francorchamps paddock is that Formula 1 is in fact poised to confirm the Qatar news by the end of the Belgian GP weekend.

But there are several other question marks on the remainder of the 2021 calendar, including Brazil, Mexico and Turkey which are all on the UK's covid travel "red list".

Sky Italia mentioned Mugello as a potential substitute in the event of several more cancellations.

"Realistically speaking, we are targeting 22 races," Domenicali admits.

"That would be a huge success because that number has never happened before in Formula 1 and we should not forget that, particularly in a year of covid."

According to Haas boss Gunther Steiner, however, the teams are still in the dark as to what exactly Formula 1 is planning and any knock-on implications.

"No, there have been no negotiations with the teams yet," he said.

"I'm sure Stefano and everyone else in F1 are planning intensively and I understand that correctly organising races takes time.

"At the same time it is necessary for us to take care of all the logistics in advance. Any wrong decision is very expensive, but I completely trust Stefano and his team," Steiner added.

"Let's hope they come up with a good calendar, even if they have to skip something. I do not know the commercial situation and this is none of our business.

"We proceed from the assumption that any version of the calendar that suits them will suit us as well. Even if there are one or two fewer races, this year's season is going great anyway," said the Haas chief.