Ricciardo at AlphaTauri? According to Tost, it is possible

Aston Martin's personnel problems show how necessary a reserve driver is. If the British team is also unable to have Lance Stroll at the next Bahrain Grand Prix (and possibly longer), Felipe Drugovich may come into action. The Brazilian drove all his laps during the first day of winter testing.

It may also happen to AlphaTauri that Yuki Tsunoda or Nyck de Vries have to miss a race due to circumstances. In that case, the Italian team can draw from Red Bull Racing's pool of test and reserve drivers. This includes Daniel Ricciardo. Should the need arise at AlphaTauti, would a return of the Australian to Red Bull's sister team be possible, team boss Franz Tost was asked?

"Theoretically, yes. Practically, I don't hope so", Tost told The Race. "Because there are other young drivers - like Liam Lawson, like [Isack] Hadjar. I think that we primarily will be focused on the young drivers. Because that's within our philosophy."

Ricciardo drove for Toro Rosso, AlphaTauri's predecessor, in 2012 and 2013. In 2014, he was promoted to Red Bull Racing. With that team, the Australian has now returned as a test and reserve driver. Should Max Verstappen or Sergio Perez be unavailable, he could fill in at Red Bull.