What is this all about
What was the Mercedes contract pic about?
It seems that Mercedes knew about Ricciardo's announcement and were trolling him with that tweet
It is interesting to note that Danny Ric had an interview with F1.com on the 2nd of August, just one day before his announcement and told them "I expect to re-sign for Red Bull and you can expect an announcement before Spa"
I would have thought (as I mentioned above) that Sainz would just drop-in and replace Ricciardo at Red Bull as he is a signed Red Bull driver, but and it is a big but, Max is now the number one driver in the team and he and Sainz don't get along at all. When Verstappen and Sainz were together at Toro Rosso the team had a very hard time handling the pairing as apparently "they fought like cat and dog, so maybe it isn't as simple as I thought. Max having a father who was an F1 driver may have an extremely good contract, which could include him having a say in who is his team mate, like it has been reported for Hamilton and Vettel. But Red Bull are a "different" type of team and I'm not sure Helmut Marko would allow such a clause, the counter to that is Red Bull wanted to keep Max and may have allowed him to add such a clause in his contract, I guess time will tell. I don't really see any other driver on Red Bulls books at the moment who is better than Sainz.
Sainz has been in talks with McLaren to replace Alonso, so that could be a solution for him if Red Bull (or Max) decide not to sign him. Pierre Gasly has impressed at Toro Rosso but if he were to move up to Red Bull who would replace him at Toro Rosso? Looking at the Red Bull stable of young drivers there isn't a qualified youngster seemingly in a position to step in up, none of their young drivers has enough points to get a super license. And what about Brendon Hartley, it seems from the press that Toro Rosso were looking to replace him at the end of the season, so if Gasly were to move up, Toro Rosso could be in a position to need 2 drivers with none of their junior drivers having a super license.
I believe that Honda will want to place a Japanese driver in the team at some point very soon, so Toro Rosso could really only be looking for a driver for one season. I think a solution could be that Sainz moves to McLaren (if Alonso leaves) and the young British McLaren driver Lando Norris moves to Toro Rosso as a replacement for Gasly, who himself moves to Red Bull. I seem to remember reading that Toro Rosso were looking at replacing Hartley with Norris, so if there is a vacant seat it could make sense.
So what if any, are the knock-on effect of Ricciardo's move on other teams and drivers? Well clearly it has a big effect on French driver Esteban Ocon was bound for Renault, if news reports are to be believed, so it could/will have an effect on Force India. But it looks likely that the Stroll family could have some investment in the new ownership of Force India, which would surely mean Lance Stroll would move there, leaving a space at Williams. Could that be a good place for Mercedes protege and Formula Two leader George Russell to move to Williams (with some financial help from Mercedes for Williams with their engine supply).
I think other changes could be in the offing depending on what Ferrari do about replacing Kimi. Charles Leclerc is tipped to replace him and that would leave an opening at Sauber. We also have reports that Haas want to replace Romain Grosjean, could Kimi move to Sauber or Haas?
One thing is for sure I don't think we have seen the end of driver changes yet this season. Also does Danny Ric's move signal that Red Bull will for sure be running a Honda power-unit in 2019 and could that be one of the reasons he has moved?