@andae23 – Not at all. Sauber have always said that Sirotkin needs assessment, and that they aren’t afraid to delay his debut by a season if need be. From the sounds of things, Sirotkin and the Russians know this and are happy with it.
As for Gutierrez, his seat depends on his backing. With the investment from Russia, that backing might not be enough to save him. Especially if his results don’t improve – the Slims could simply write him off and focus on McLaren.
Hulkenberg’s departure is no sure thing, either. Rumours were flying that he was about to leave, and then came to nothing. The car’s performace has improved, though not by leaps and bounds. And while he has been linked to a move to Ferrari, so to have Raikkonen, Button and Massa has been given a vote if confidence by Luca. In four years, Hulkenberg has raced for three teams and spent a year on the sidelines. A move away from Sauber with no certain future could kill his career.
And given the close relationship between Sauber and Ferrari, Jules Bianchi could get promoted.