Red Bull is no longer ruling out replacing Alex Albon.

Until very recently, the energy drink-owned marque has been strongly backing the British-born Thai driver amid calls for him to be replaced.

But now, top drivers Sergio Perez and Nico Hulkenberg are on the market, just as Albon's recent improvement hit a snag with a poor outing at Sochi.

"If Alex Albon performs well, he stays," Dr Helmut Marko, the architect of Red Bull's notorious driver program, told Speed Week.

"If not, there will be a deliberation," he added when asked about Perez and Hulkenberg's candidatures.

"We would then see which good drivers are on the market. But that's not an issue at the moment," said Marko.

Also possible is that, in light of Honda's shock decision to quit Formula 1, Red Bull might also be needing to fill Max Verstappen's cockpit.

However, former F1 driver Christijan Albers doubts that.

"As long as Hamilton continues to drive for Mercedes, I see no opportunity for Verstappen to go there," he told De Telegraaf.

"Not because Max doesn't want it, because he wouldn't care, but because Lewis Hamilton would never allow it."