Source: https://twitter.com/redbullracing/status/1595401790169694211
Unexpected, does he aim at Perez's seat?
I really don't understand Ricciardo. I mean that he left Red Bull not to be the second driver there. He was having serious problems with Verstappen there as well. You must be remembering their silly accident in 2018 Azerbaijan Grand Prix too. Considering all of these things I just don't see any reason for him to return here as long as Verstappen is the main driver of the team. It is obvious that Verstappen will be permanent here for many more years. Ricciardo can take only Perez's place.
Instead he could have joined Mercedes as the third driver and it would have been more sensible for him. After Hamilton retires he would have made up a nice team with Russell there.
Maybe RIcciardo thinks that he is not dreaming anymore of getting world title and thus he may have promised Redbull that I will act as a second driver for the team when Perez leaves or is sacked as long as Verstappen is here and I will only fight for the title if Verstappen performs really badly which is highly unlikely.
I agree,the best option would have been Mercedes as once Hamilton would retire probably at the end of the next season or just a bit more because his age does not permit him anymore to have better reflexes than 20-26 years old talented drivers like Verstappen is and then Ricciardo could have tried one last time the fight for the title.