Cadena SER -that is Spain's largest radio broadcaster- is running the story that Alonso will be returning to F1 with Renault "as soon as possible": https://cadenaser.com/ser/2020/07/02...32_457561.html

The agreement between the two parties will be announced in the coming days and depends on more than one factor, such as the relationship between Renault and Ricciardo, as explained by José Antonio Ponseti in 'La Ventana'. The team wants the Australian to leave the team but we will have to see when and on what terms.

It is almost certain that Fernando Alonso will not be able to make his debut in the first race of the 2020 World Championship, which will be held next weekend in Austria, but it is possible that he will do so later, although we will have to wait for the announcement of the two parties to know that detail. The idea is that the return occurs as soon as possible.
I don't know what to make of this, but it's a very interesting claim. As much as I dislike Spanish press, Cadena SER is fairly reputable - this is definitely not Marca. That said, it's hard to see how Renault would pay Ricciardo to sit out most of the 2020 season on top of paying Alonso's wages, which can't be cheap. The only reasonable chance for that would be that McLaren kicked Sainz out to make way for Ricciardo and I can't see them doing that.