@shadow13 i really doubt they would take Massa. He might be a number 2 driver, but he is scoring no points at all, and pertly he was the reason that Ferrari didn’t manage to be 2nd in the constructors championship last year. Webber isn’t even good enough this year, he is really not doing very well to hold up the others if he were to be the number 2 driver, which i don’t think they try to make him. I just think the pieces fall into Vettel’s hands a little easier because he is quicker and ahead on points. But Rosberg is a good bet. I don’t think he would mind leaving Mercedes for a seat at Red Bull, and i certainly don’t think him and Vettel would clash, like i sadly do think would happen if Hamilton joined the team. Mainly because Rosberg seems more relaxed, then Hamilton does, and he is still a very good and consistent driver.
I doubt that RB will sack Webber mid season, mainly because it would jeopardize their constructors title unnecessarily and because it is generally quite hard to find good drivers that are willing to change team half way though a season.
But if they don’t renew Webber’s contract by the end of the year, i think that Rosberg will be considered as a possible replacement.